There had been small-scale immigration from Britain since the 12th century, after the Anglo-Norman invasion. By the 15th century, many of these settlers had assimilated into Irish culture and direct English control had shrunk to an area called the Pale. In the 1540s the English began colonizing the island, beginning the Tudor conquest of Ireland. The first plantations were in the 1550s, during the reign of Queen Mary I, in Laois ('Queen's County') and Offaly ('King's County'). These plantations were based around existing frontier forts, but they were largely unsuccessful due to attacks from the local Irish clans.