Abernethy is a name which has been around much longer than the Leslie name. (In the Scot clan system, Abernethy became a "sept" of the Leslie Clan.) It combines two Celtic words 'Aber' which means confluence and 'Nethy' which is the name of the river which joins the Earn and then drains into the Firth of Tay. Abernethy is an ancient Pictish place which, in the 4th century, was the center for the now Christian Southern Picts. In 460 AD the King of the Picts, Nechtan, granted some of the land in this area to build a church. In 850 AD Garmaidh, then King of the Picts, had built another church in the area where the famous Round Tower was built. This round tower is now one of only two remaining Celtic structures left in Scotland. The tower was left in hereditary right to the Culdees (Celtic Clergy) who would later become the lay abbots and lords of Abernethy. In the 12th century the last of the lay abbots, Ethefred, became a secular peer. Etheked's great grandson, Orm, greatly increased the Abernethy holdings by obtaining grants of land from Scotlands King William The Lion. Lawrence was a counselor to King William and was also one of the guarantors of the Treaty of 1189.
Lawrence1s grandson, Sir Hugh De Abernethy, was involved in the kidnapping of King Alexander III. Hugh was later pardoned for the abduction. After King Alexander III died at age 45, the kingdom was out of control. The regent was the Earl of Fife. Hugh, along with his two sons Patrick and William along with Sir Walter Percy were involved in the assassination of the Earl of Fife. Sir Walter Percy was captured and executed for the murder. Sir Hugh and his son William were also caught and sent to prison where they both died, and Patrick, the killer, managed to escape and fled to France where he ended his days.