Up until this period the O'Donovans and O'Mahonys are generally regarded to have been allies, their ancestors Máel Muad mac Brain and Donnubán having joined forces against the Dál gCais in the 10th century. In 1283, following an attempted coup within the MacCarthy, a number of MacCarthys and some O'Donovans migrated into new territory adjacent to the O'Sullivans, which commenced a long and tumultuous relationship between O'Donovans and both major septs of the O'Sullivans, and which has included both minor warfare as well as intermarriage over the next four centuries.