I am researching CALLAGHANs from Ireland and am interested in finding out about the time before people used surnames. I have done a Y chromosone DNA test and have found connections like apparent ancesters with 'non-Callaghan' surnames, presumably connected before surnames were used. Does anyone know how, where and when the surname CALLAGHAN came about and what happened before that time. I know it has connections with Co. Cork and the King of Munster. Tim