Irish immigration to Puerto Rico began during the period of Spanish colonization of the island, continuing through 19th century to the present day. During the 16th century, many Irishmen, who were known as "Wild Geese", deserted from the English Army and joined the Spanish Army. They did so either in Europe or when they could "jump ship" off the coast of Puerto Rico (whenever English ships came to trade or when the Royal Navy was engaged in attacks against the Spanish colonial forces on the island), at which time they joined the Spanish colonial army, mainly in San Juan.