The MRCA estimate for this group puts its age at around 800 AD. The date estimate means this group very likely predates the arrival of the Normans, and probably predates the Vikings as well. So these Curleys most likely descend from a Gaelic tribe that's been in Ireland since before 800 AD. Some of these surnames, including the Curleys, make their first appearance in the area around the 1500's. So it looks like these were some native Irish folk who took on various surnames around the 1500's. Some of these surnames may have been picked up from other lineages already present in the area. Others may have been entirely new, previously unused as surnames.