[1] In 1611 Christiaensen paid two visits to Manhattan in his ship Fortuyn, including one with fellow explorer Adriaen Block in his Tyger.
Upon his return to the Dutch Republic in 1612, he brought back with him two young Native Americans who were the sons of a local sachem.
In 1613 Christiaensen and Block returned in the two vessels,[2] and created the first map of the region that showed Manhattan and Long Island as separate geographical entities.
In 1614 Christiensen sailed the Fortuyn up the North River to Castle Island (New York), where he built a warehouse on the ruins of an old abandoned French fur trader's fort.
Christiensen took two cannon and eleven swivel guns from the Fortuyn and left twelve men under the command of Jacob Eelkens, before returning downriver.