Ryan

It should also be listed as an Anglicized form of Riain. It isn't just a surname name.

Ryan was almost unheard of as a first name (except perhaps in families where it was the mother's or grandmother's maiden name) until 1964, when it was popularized by the American actor Ryan O'Neal (born 1941) because of his role in the very popular night time soap opera Peyton Place. O'Neal played the love interest opposite a young Mia Farrow. The name's popularity probably increased because of O'Neal's role in the sentimental 1974 movie Love Story.