The colour combination of orange, white, and blue is commonly considered the first Dutch flag. The 400th anniversary of the introduction of the Dutch flag was commemorated in the Netherlands by the issue of a postage stamp in 1972. That was based on the fact that in 1572 the "Watergeuzen" ("Gueux de mer", "Sea Beggars"), the pro-Dutch privateers, captured Den Briel in name of William, Prince of Orange. However, it is uncertain whether they took an orange-white-blue flag with them on the event, although they certainly started using an orange-white-blue tricolour somewhat later in the 1570s. It became later known as the Prinsenvlag ("Prince's flag") and served as the basis for the former South African flag, the flags of New York City and the Flag of Albany, New York, all three former dominions of the Dutch Republic.