diff --git a/docs/split-stream.md b/docs/split-stream.md
index ad10e6122..13430283a 100644
--- a/docs/split-stream.md
+++ b/docs/split-stream.md
@@ -82,6 +82,72 @@ This impacts only the aggregate loaded by the repository. Subscriptions will sti
 You can combine this feature with the snapshot feature to increase the performance even more.
 :::
 
+## Dynamic Consistency Boundary
+
+Projections of the [dynamic consistency boundary](dynamic-consistency-boundary.md) also respect `#[SplitStream]`.
+If a projection has an apply method for such an event,
+the decision model is only built from the last of these events matching the projection's tags onwards.
+No configuration is needed and nothing is archived, other projections and subscriptions still see all events.
+
+```php
+use Patchlevel\EventSourcing\Attribute\Apply;
+use Patchlevel\EventSourcing\Projection\BasicProjection;
+
+final class Balance extends BasicProjection
+{
+    public function __construct(
+        private readonly BankAccountId $bankAccountId,
+    ) {
+    }
+
+    public function initialState(): int
+    {
+        return 0;
+    }
+
+    /** @return list<string> */
+    protected function tagFilter(): array
+    {
+        return ["bank_account:{$this->bankAccountId->toString()}"];
+    }
+
+    #[Apply]
+    public function applyBalanceReported(int $state, BalanceReported $event): int
+    {
+        return $event->balanceInCents;
+    }
+
+    #[Apply]
+    public function applyMoneyDeposited(int $state, MoneyDeposited $event): int
+    {
+        return $state + $event->amountInCents;
+    }
+}
+```
+:::note
+Only the split events of the projection itself are considered.
+A `BalanceReported` of another bank account does not cut off the history of this one,
+and other projections in the same decision model still get all events they need.
+:::
+
+If a projection handles a split event but needs the whole history anyway, for example to count them,
+you can opt out by overriding `splitEvents`.
+
+```php
+use Patchlevel\EventSourcing\Projection\BasicProjection;
+
+final class NumberOfBalanceReports extends BasicProjection
+{
+    // ...
+
+    /** @return list<class-string> */
+    public function splitEvents(): array
+    {
+        return [];
+    }
+}
+```
+
 ## Learn more
 
 * [How to use message decorator](message-decorator.md)
diff --git a/src/DecisionModel/StoreDecisionModelBuilder.php b/src/DecisionModel/StoreDecisionModelBuilder.php
index 7eaef7b6b..dad0e51d9 100644
--- a/src/DecisionModel/StoreDecisionModelBuilder.php
+++ b/src/DecisionModel/StoreDecisionModelBuilder.php
@@ -6,10 +6,12 @@
 
 use Patchlevel\EventSourcing\Projection\CompositeProjection;
 use Patchlevel\EventSourcing\Projection\Projection;
+use Patchlevel\EventSourcing\Projection\SplitStreamPositions;
 use Patchlevel\EventSourcing\Store\AppendCondition;
 use Patchlevel\EventSourcing\Store\AppendStore;
 
 use function max;
+use function min;
 
 /** @experimental */
 final class StoreDecisionModelBuilder implements DecisionModelBuilder
@@ -23,10 +25,11 @@ public function __construct(
     public function build(
         array $projections,
     ): DecisionModel {
-        $projection = new CompositeProjection($projections);
+        $from = SplitStreamPositions::resolve($this->store, $projections);
+        $projection = new CompositeProjection($projections, $from);
 
         $query = $projection->query();
-        $stream = $this->store->query($query);
+        $stream = $this->store->query($query, $from === [] ? 0 : min($from));
 
         $state = $projection->initialState();
 
diff --git a/src/Projection/BasicProjection.php b/src/Projection/BasicProjection.php
index 8a9d0b5c8..a022e9644 100644
--- a/src/Projection/BasicProjection.php
+++ b/src/Projection/BasicProjection.php
@@ -5,6 +5,7 @@
 namespace Patchlevel\EventSourcing\Projection;
 
 use Patchlevel\EventSourcing\Attribute\Apply;
+use Patchlevel\EventSourcing\Attribute\SplitStream;
 use Patchlevel\EventSourcing\Message\Message;
 use Patchlevel\EventSourcing\Store\SubQuery;
 use ReflectionClass;
@@ -13,10 +14,12 @@
 use ReflectionNamedType;
 use ReflectionUnionType;
 
+use function array_filter;
 use function array_key_exists;
 use function array_keys;
 use function array_map;
 use function array_merge;
+use function array_values;
 use function class_exists;
 
 /**
@@ -24,7 +27,7 @@
  * @template S = mixed
  * @implements Projection<S>
  */
-abstract class BasicProjection implements Projection, SubQueryProvider
+abstract class BasicProjection implements Projection, SubQueryProvider, SplitStreamProvider
 {
     /** @var array<class-string, string>|null $applyMethods */
     private array|null $applyMethods = null;
@@ -67,6 +70,15 @@ public function subQuery(): SubQuery
         return $this->subQuery;
     }
 
+    /** @return list<class-string> */
+    public function splitEvents(): array
+    {
+        return array_values(array_filter(
+            $this->eventTypeFilter(),
+            static fn (string $eventClass): bool => (new ReflectionClass($eventClass))->getAttributes(SplitStream::class) !== [],
+        ));
+    }
+
     /** @return list<class-string> */
     protected function eventTypeFilter(): array
     {
diff --git a/src/Projection/CompositeProjection.php b/src/Projection/CompositeProjection.php
index 4271aea8c..409880ceb 100644
--- a/src/Projection/CompositeProjection.php
+++ b/src/Projection/CompositeProjection.php
@@ -5,6 +5,7 @@
 namespace Patchlevel\EventSourcing\Projection;
 
 use Patchlevel\EventSourcing\Message\Message;
+use Patchlevel\EventSourcing\Store\Header\IndexHeader;
 use Patchlevel\EventSourcing\Store\Query;
 
 use function array_map;
@@ -12,9 +13,13 @@
 /** @experimental */
 final class CompositeProjection
 {
-    /** @param array<string, Projection> $projections */
+    /**
+     * @param array<string, Projection>     $projections
+     * @param array<string, positive-int|0> $from        messages before this index are not applied to the projection
+     */
     public function __construct(
         private readonly array $projections,
+        private readonly array $from = [],
     ) {
     }
 
@@ -51,6 +56,13 @@ public function initialState(): array
     public function apply(mixed $state, Message $message): mixed
     {
         foreach ($this->projections as $name => $projection) {
+            if (
+                ($this->from[$name] ?? 0) > 0
+                && $message->header(IndexHeader::class)->index < $this->from[$name]
+            ) {
+                continue;
+            }
+
             $state[$name] = $projection->apply($state[$name], $message);
         }
 
diff --git a/src/Projection/SplitStreamPositions.php b/src/Projection/SplitStreamPositions.php
new file mode 100644
index 000000000..4adfcdfba
--- /dev/null
+++ b/src/Projection/SplitStreamPositions.php
@@ -0,0 +1,68 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Projection;
+
+use Patchlevel\EventSourcing\Store\AppendStore;
+use Patchlevel\EventSourcing\Store\Query;
+use Patchlevel\EventSourcing\Store\SubQuery;
+
+use function array_map;
+use function array_values;
+use function max;
+
+/** @internal */
+final class SplitStreamPositions
+{
+    /**
+     * Returns for each projection the index from which on it needs events.
+     * That is the index of its last split event, or 0 if it has none.
+     *
+     * @param array<string, Projection> $projections
+     *
+     * @return array<string, positive-int|0>
+     */
+    public static function resolve(AppendStore $store, array $projections): array
+    {
+        $positions = array_map(static fn (): int => 0, $projections);
+        $lookups = [];
+
+        foreach ($projections as $name => $projection) {
+            if (!$projection instanceof SplitStreamProvider || !$projection instanceof SubQueryProvider) {
+                continue;
+            }
+
+            $splitEvents = $projection->splitEvents();
+
+            if ($splitEvents === []) {
+                continue;
+            }
+
+            $subQuery = $projection->subQuery();
+
+            $lookups[$name] = new SubQuery(
+                $subQuery->tags,
+                $splitEvents,
+                $subQuery->streamName,
+                true,
+            );
+        }
+
+        if ($lookups === []) {
+            return $positions;
+        }
+
+        foreach ($store->query(new Query(...array_values($lookups))) as $index => $message) {
+            foreach ($lookups as $name => $lookup) {
+                if (!$lookup->match($message)) {
+                    continue;
+                }
+
+                $positions[$name] = max($positions[$name], $index);
+            }
+        }
+
+        return $positions;
+    }
+}
diff --git a/src/Projection/SplitStreamProvider.php b/src/Projection/SplitStreamProvider.php
new file mode 100644
index 000000000..6034b4533
--- /dev/null
+++ b/src/Projection/SplitStreamProvider.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Projection;
+
+/** @experimental */
+interface SplitStreamProvider
+{
+    /**
+     * Events which contain the whole state the projection needs.
+     * Everything before the last of these events is not loaded anymore.
+     *
+     * @return list<class-string>
+     */
+    public function splitEvents(): array;
+}
diff --git a/src/Projection/StoreProjectionBuilder.php b/src/Projection/StoreProjectionBuilder.php
index 852ee0d08..da7f01da3 100644
--- a/src/Projection/StoreProjectionBuilder.php
+++ b/src/Projection/StoreProjectionBuilder.php
@@ -6,6 +6,8 @@
 
 use Patchlevel\EventSourcing\Store\AppendStore;
 
+use function min;
+
 /** @experimental */
 final class StoreProjectionBuilder implements ProjectionBuilder
 {
@@ -22,10 +24,11 @@ public function __construct(
     public function build(
         array $projections,
     ): array {
-        $projection = new CompositeProjection($projections);
+        $from = SplitStreamPositions::resolve($this->store, $projections);
+        $projection = new CompositeProjection($projections, $from);
 
         $query = $projection->query();
-        $stream = $this->store->query($query);
+        $stream = $this->store->query($query, $from === [] ? 0 : min($from));
 
         $state = $projection->initialState();
 
diff --git a/tests/Unit/DecisionModel/StoreDecisionModelBuilderTest.php b/tests/Unit/DecisionModel/StoreDecisionModelBuilderTest.php
index 5de35fa13..e03567e1e 100644
--- a/tests/Unit/DecisionModel/StoreDecisionModelBuilderTest.php
+++ b/tests/Unit/DecisionModel/StoreDecisionModelBuilderTest.php
@@ -4,11 +4,14 @@
 
 namespace Patchlevel\EventSourcing\Tests\Unit\DecisionModel;
 
+use Patchlevel\EventSourcing\Attribute\Apply;
 use Patchlevel\EventSourcing\DecisionModel\StoreDecisionModelBuilder;
 use Patchlevel\EventSourcing\Message\Message;
 use Patchlevel\EventSourcing\Message\Stream;
+use Patchlevel\EventSourcing\Projection\BasicProjection;
 use Patchlevel\EventSourcing\Store\AppendCondition;
 use Patchlevel\EventSourcing\Store\AppendStore;
+use Patchlevel\EventSourcing\Store\Header\IndexHeader;
 use Patchlevel\EventSourcing\Store\Header\TagsHeader;
 use Patchlevel\EventSourcing\Store\InMemoryStore;
 use Patchlevel\EventSourcing\Store\Query;
@@ -18,6 +21,9 @@
 use Patchlevel\EventSourcing\Tests\Unit\Fixture\LastEmailProjection;
 use Patchlevel\EventSourcing\Tests\Unit\Fixture\ProfileCreated;
 use Patchlevel\EventSourcing\Tests\Unit\Fixture\ProfileId;
+use Patchlevel\EventSourcing\Tests\Unit\Fixture\ProfileVisited;
+use Patchlevel\EventSourcing\Tests\Unit\Fixture\SplittingEvent;
+use Patchlevel\EventSourcing\Tests\Unit\Fixture\VisitsProjection;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 
@@ -115,4 +121,165 @@ public function testEmptyStream(): void
 
         self::assertEquals(new AppendCondition($expectedQuery, 0), $state->appendCondition);
     }
+
+    public function testSplitStream(): void
+    {
+        $store = new InMemoryStore();
+        $store->save(
+            $this->visited('1', ['profile-1']),
+            $this->visited('1', ['profile-1']),
+            $this->split(10, ['profile-1']),
+            $this->visited('1', ['profile-1']),
+            $this->split(99, ['profile-2']),
+            $this->visited('1', ['profile-1']),
+        );
+
+        $builder = new StoreDecisionModelBuilder($store);
+
+        $state = $builder->build([
+            'visits' => new VisitsProjection(['profile-1']),
+        ]);
+
+        self::assertSame(['visits' => 12], $state->state);
+        self::assertSame(6, $state->appendCondition->after);
+    }
+
+    public function testSplitStreamReadsFromLastSplitEvent(): void
+    {
+        $splitMessage = $this->split(10, ['profile-1'])->withHeader(new IndexHeader(3));
+
+        $expectedQuery = new Query(
+            new SubQuery(['profile-1'], [ProfileVisited::class, SplittingEvent::class]),
+        );
+
+        $store = new class ($splitMessage) implements AppendStore {
+            /** @var list<array{Query, int}> */
+            public array $calls = [];
+
+            public function __construct(
+                private readonly Message $splitMessage,
+            ) {
+            }
+
+            /** @param iterable<Message> $messages */
+            public function append(iterable $messages, AppendCondition|null $appendCondition = null): void
+            {
+            }
+
+            public function query(Query $query, int $from = 0): Stream
+            {
+                $this->calls[] = [$query, $from];
+
+                return new Stream([3 => $this->splitMessage]);
+            }
+        };
+
+        $builder = new StoreDecisionModelBuilder($store);
+
+        $state = $builder->build([
+            'visits' => new VisitsProjection(['profile-1']),
+        ]);
+
+        self::assertSame(['visits' => 10], $state->state);
+        self::assertEquals(new AppendCondition($expectedQuery, 3), $state->appendCondition);
+        self::assertEquals(
+            [
+                [new Query(new SubQuery(['profile-1'], [SplittingEvent::class], null, true)), 0],
+                [$expectedQuery, 3],
+            ],
+            $store->calls,
+        );
+    }
+
+    public function testSplitStreamWithoutSplitEvent(): void
+    {
+        $store = new InMemoryStore();
+        $store->save(
+            $this->visited('1', ['profile-1']),
+            $this->visited('1', ['profile-1']),
+        );
+
+        $builder = new StoreDecisionModelBuilder($store);
+
+        $state = $builder->build([
+            'visits' => new VisitsProjection(['profile-1']),
+        ]);
+
+        self::assertSame(['visits' => 2], $state->state);
+    }
+
+    public function testSplitStreamWithProjectionWithoutSplitEvents(): void
+    {
+        $store = new InMemoryStore();
+        $store->save(
+            Message::create(new ProfileCreated(ProfileId::fromString('1'), Email::fromString('info@patchlevel.de')))
+                ->withHeader(new TagsHeader(['profile-1'])),
+            $this->visited('1', ['profile-1']),
+            $this->split(10, ['profile-1']),
+            $this->visited('1', ['profile-1']),
+        );
+
+        $builder = new StoreDecisionModelBuilder($store);
+
+        $state = $builder->build([
+            'created' => new IncrementProjection(0, ['profile-1']),
+            'visits' => new VisitsProjection(['profile-1']),
+        ]);
+
+        self::assertSame(['created' => 1, 'visits' => 11], $state->state);
+    }
+
+    public function testSplitStreamOptOut(): void
+    {
+        $store = new InMemoryStore();
+        $store->save(
+            $this->split(10, ['profile-1']),
+            $this->split(20, ['profile-1']),
+        );
+
+        $builder = new StoreDecisionModelBuilder($store);
+
+        $state = $builder->build([
+            'splits' => new class extends BasicProjection {
+                public function initialState(): int
+                {
+                    return 0;
+                }
+
+                #[Apply]
+                public function applySplittingEvent(int $state, SplittingEvent $event): int
+                {
+                    return $state + 1;
+                }
+
+                /** @return list<class-string> */
+                public function splitEvents(): array
+                {
+                    return [];
+                }
+
+                /** @return list<string> */
+                protected function tagFilter(): array
+                {
+                    return ['profile-1'];
+                }
+            },
+        ]);
+
+        self::assertSame(['splits' => 2], $state->state);
+    }
+
+    /** @param list<string> $tags */
+    private function visited(string $id, array $tags): Message
+    {
+        return Message::create(new ProfileVisited(ProfileId::fromString($id)))
+            ->withHeader(new TagsHeader($tags));
+    }
+
+    /** @param list<string> $tags */
+    private function split(int $visits, array $tags): Message
+    {
+        return Message::create(new SplittingEvent(Email::fromString('info@patchlevel.de'), $visits))
+            ->withHeader(new TagsHeader($tags));
+    }
 }
diff --git a/tests/Unit/Fixture/VisitsProjection.php b/tests/Unit/Fixture/VisitsProjection.php
new file mode 100644
index 000000000..eefc02003
--- /dev/null
+++ b/tests/Unit/Fixture/VisitsProjection.php
@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Patchlevel\EventSourcing\Tests\Unit\Fixture;
+
+use Patchlevel\EventSourcing\Attribute\Apply;
+use Patchlevel\EventSourcing\Projection\BasicProjection;
+
+final class VisitsProjection extends BasicProjection
+{
+    /** @param list<string> $tags */
+    public function __construct(
+        private readonly array $tags,
+    ) {
+    }
+
+    public function initialState(): int
+    {
+        return 0;
+    }
+
+    #[Apply]
+    public function applyProfileVisited(int $state, ProfileVisited $event): int
+    {
+        return $state + 1;
+    }
+
+    #[Apply]
+    public function applySplittingEvent(int $state, SplittingEvent $event): int
+    {
+        return $event->visits;
+    }
+
+    /** @return list<string> */
+    protected function tagFilter(): array
+    {
+        return $this->tags;
+    }
+}
diff --git a/tests/Unit/Projection/BasicProjectionTest.php b/tests/Unit/Projection/BasicProjectionTest.php
index 12e41ca46..c2951494f 100644
--- a/tests/Unit/Projection/BasicProjectionTest.php
+++ b/tests/Unit/Projection/BasicProjectionTest.php
@@ -12,9 +12,12 @@
 use Patchlevel\EventSourcing\Store\Header\TagsHeader;
 use Patchlevel\EventSourcing\Store\SubQuery;
 use Patchlevel\EventSourcing\Tests\Unit\Fixture\Email;
+use Patchlevel\EventSourcing\Tests\Unit\Fixture\IncrementProjection;
 use Patchlevel\EventSourcing\Tests\Unit\Fixture\ProfileCreated;
 use Patchlevel\EventSourcing\Tests\Unit\Fixture\ProfileId;
 use Patchlevel\EventSourcing\Tests\Unit\Fixture\ProfileVisited;
+use Patchlevel\EventSourcing\Tests\Unit\Fixture\SplittingEvent;
+use Patchlevel\EventSourcing\Tests\Unit\Fixture\VisitsProjection;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 use Stringable;
@@ -53,6 +56,20 @@ public function applyProfileCreated(int $state, ProfileCreated $event): int
         self::assertSame($projection->subQuery(), $projection->subQuery());
     }
 
+    public function testSplitEvents(): void
+    {
+        $projection = new VisitsProjection([]);
+
+        self::assertSame([SplittingEvent::class], $projection->splitEvents());
+    }
+
+    public function testNoSplitEvents(): void
+    {
+        $projection = new IncrementProjection(0);
+
+        self::assertSame([], $projection->splitEvents());
+    }
+
     public function testApplyWithNonMatchingMessage(): void
     {
         $projection = new class extends BasicProjection {
diff --git a/tests/Unit/Projection/CompositeProjectionTest.php b/tests/Unit/Projection/CompositeProjectionTest.php
index 4d965d3f0..c5d83fd05 100644
--- a/tests/Unit/Projection/CompositeProjectionTest.php
+++ b/tests/Unit/Projection/CompositeProjectionTest.php
@@ -7,6 +7,7 @@
 use Patchlevel\EventSourcing\Message\Message;
 use Patchlevel\EventSourcing\Projection\CompositeProjection;
 use Patchlevel\EventSourcing\Projection\Projection;
+use Patchlevel\EventSourcing\Store\Header\IndexHeader;
 use Patchlevel\EventSourcing\Store\Header\StreamNameHeader;
 use Patchlevel\EventSourcing\Store\Header\TagsHeader;
 use Patchlevel\EventSourcing\Store\Query;
@@ -77,6 +78,29 @@ public function testApplyDelegatesToEachProjection(): void
         self::assertSame(11, $newState['y']);
     }
 
+    public function testApplySkipsMessagesBeforeFrom(): void
+    {
+        $composite = new CompositeProjection(
+            [
+                'x' => new IncrementProjection(0, ['match']),
+                'y' => new IncrementProjection(0, ['match']),
+            ],
+            ['y' => 2],
+        );
+
+        $message = Message::create(new ProfileCreated(
+            ProfileId::fromString('test'),
+            Email::fromString('foo@example.com'),
+        ))
+            ->withHeader(new TagsHeader(['match']));
+
+        $state = $composite->initialState();
+        $state = $composite->apply($state, $message->withHeader(new IndexHeader(1)));
+        $state = $composite->apply($state, $message->withHeader(new IndexHeader(2)));
+
+        self::assertSame(['x' => 2, 'y' => 1], $state);
+    }
+
     public function testApplySkipsNonMatchingProjection(): void
     {
         $composite = new CompositeProjection([
diff --git a/tests/Unit/Projection/StoreProjectionBuilderTest.php b/tests/Unit/Projection/StoreProjectionBuilderTest.php
index 509e41465..22f90b8c5 100644
--- a/tests/Unit/Projection/StoreProjectionBuilderTest.php
+++ b/tests/Unit/Projection/StoreProjectionBuilderTest.php
@@ -10,10 +10,14 @@
 use Patchlevel\EventSourcing\Projection\StoreProjectionBuilder;
 use Patchlevel\EventSourcing\Store\AppendStore;
 use Patchlevel\EventSourcing\Store\Header\TagsHeader;
+use Patchlevel\EventSourcing\Store\InMemoryStore;
 use Patchlevel\EventSourcing\Tests\Unit\Fixture\Email;
 use Patchlevel\EventSourcing\Tests\Unit\Fixture\IncrementProjection;
 use Patchlevel\EventSourcing\Tests\Unit\Fixture\ProfileCreated;
 use Patchlevel\EventSourcing\Tests\Unit\Fixture\ProfileId;
+use Patchlevel\EventSourcing\Tests\Unit\Fixture\ProfileVisited;
+use Patchlevel\EventSourcing\Tests\Unit\Fixture\SplittingEvent;
+use Patchlevel\EventSourcing\Tests\Unit\Fixture\VisitsProjection;
 use PHPUnit\Framework\Attributes\CoversClass;
 use PHPUnit\Framework\TestCase;
 
@@ -42,4 +46,19 @@ public function testBuild(): void
 
         self::assertSame(['count' => 2], $builder->build($projections));
     }
+
+    public function testBuildWithSplitStream(): void
+    {
+        $store = new InMemoryStore();
+        $store->save(
+            Message::create(new ProfileVisited(ProfileId::fromString('1')))->withHeader(new TagsHeader(['match'])),
+            Message::create(new SplittingEvent(Email::fromString('foo@bar.com'), 5))
+                ->withHeader(new TagsHeader(['match'])),
+            Message::create(new ProfileVisited(ProfileId::fromString('1')))->withHeader(new TagsHeader(['match'])),
+        );
+
+        $builder = new StoreProjectionBuilder($store);
+
+        self::assertSame(['visits' => 6], $builder->build(['visits' => new VisitsProjection(['match'])]));
+    }
 }