Osraige, also known as Osraighe or Ossory (modern Irish: Osraí), was a medieval Irish kingdom comprising most of present-day County Kilkenny and western County Laois. The home of the Osraige people, it existed from around the first century until the Norman invasion of Ireland in the 12th century. It was ruled by the Dál Birn dynasts, whose medieval descendants assumed the surname Mac Giolla Phádraig. The name survives in the Catholic Diocese of Ossory, established in the 5th century, which continues to use roughly the same borders.