There are stories of  Breretons on Irish soil with the armies of various monarchs, however, the histories I have prepared generally begin with the descendants of Sir William Brereton of Cheshire who arrived to fight during the time of the Battle of Maynooth.  His sons Edward, Andrew and John started branches of the Brereton family, in a number of various counties, certainly in the Counties of Offaly and Laois (which were renamed King and Queen during the time of the Plantations) also Armagh, Cork, Dublin, Kildare, Ulster, Tipperary and Wexford.