Edited sentence: The origin of the cross used in the Union Flag is unclear but many subsequent commentators have assumed that the saltire was simply taken from the arms of the FitzGeralds (or Geraldines).The use of the red saltire became more common during the German Occupation in World War II as the local population did not want to use the Union Flag in occupied territory.This explains its use before the use of the red saltire in the Union Flag.This was shown on later maps as “Ierse” (Jersey).[1] William FitzGerald, 2nd Duke of Leinster  and was incorporated into the Union Flag much later in 1801.[1] William FitzGerald, 2nd Duke of Leinster, was a prominent member of the Irish House of Lords and a founder member of the Order of Saint Patrick, who owned land on Jersey and the old Dutch map mentioned above showed his flag with the legend “Erse” (Irish) above it