Links to the St Patrick's Cross have been proposed. The St Patrick's Cross is commonly identified with the arms of the FitzGeralds, a Cambro-Norman family which became powerful in Ireland, and who also owned land in Jersey. N. V. L. Rybot in 1951 suggested that Jersey's flag originated from a mistake in a 1783 flag book by Carington Bowles, which was copied by later authors. Rybot's theory is that Bowles misinterpreted "Ierse" (Dutch for "Irish") as meaning "Jersey" in a Dutch flag-book he used as a source. However, French Admiralty charts show that Jersey was using the red saltire before 1783. In his "History of Jersey", Balleine suggests that the saltire had in fact referred to Jersey, and that some had interpreted the flag to mean Ireland. At that date, Ireland would have been written , and the book contains a different entry for Irlandois. The flag was attributed to in 1757 by French charts.