diff --git a/core/model/Versioned.php b/core/model/Versioned.php
index 320d2c7af..e683065c4 100755
--- a/core/model/Versioned.php
+++ b/core/model/Versioned.php
@@ -138,6 +138,14 @@ class Versioned extends DataObjectDecorator {
 	 */
 	private static $archive_tables = array();
 	
+	/**
+	 * Called by {@link SapphireTest} when the database is reset.
+	 * @todo Reduce the coupling between this and SapphireTest, somehow.
+	 */
+	public static function on_db_reset() {
+		self::$archive_tables = array();
+	}
+	
 	/**
 	 * Create a temporary table mapping each database record to its version on the given date.
 	 * This is used by the versioning system to return database content on that date.
diff --git a/dev/SapphireTest.php b/dev/SapphireTest.php
index c4f3a8e87..97d61f856 100644
--- a/dev/SapphireTest.php
+++ b/dev/SapphireTest.php
@@ -233,6 +233,10 @@ class SapphireTest extends PHPUnit_Framework_TestCase {
 				// echo "Deleted temp database " . $dbConn->currentDatabase() . "\n";
 				$dbConn->dropDatabase();
 			}
+			
+			// Todo: it would be good to remove this inappropriate coupling, somehow.
+			// The versioned class keeps a static cache of information about temporary tables.
+			Versioned::on_db_reset();
 		}
 	}