These dogs are mentioned, as cú (variously translated as a hound, Irish hound, war dog, wolf dog, etc.) in Irish laws and in Irish literature which dates from the 5th century.
If you are looking for a long-lived breed, the Irish Wolfhound is not for you. He lives roughly 6 to 8 years and his giant size predisposes him to many health problems.
Young Irish Wolfhounds need enough exercise to keep them lean and healthy, but not so much that their soft growing bones, joints, and ligaments become over-stressed and damaged.