Earlier, he had ridden on that horse with the daughter of Manannan Mac Lir, who had fallen in love with hiim and brought him to spend what seemed like three years in Tir na n'Og, where she was queen.  
His mother and father met after Bran and Sceolang, two of his father's hounds, refused to kill a deer which they had captured.  A druid named Fer Doirich had put a spell on his mother, Sadb, which turned her into that deer.  This man never met his own child, Plur na m'Ban, because he suffered a critical fall from his horse Embarr.  Earlier, he had ridden on that horse with the daughter of Manannan Mac Lir, who had fallen in love with hiim and brought him to spend what seemed like three years in Tir na n'Og, where she was queen.  When he returned home and touched the ground, he found that three years in fairyland are equivalent to 300 years in Ireland, and instantly became an old man.  FTP, name this warrior and bard of the Fianna, the husband of Niamh (NEEV) who, according to James Macpherson, wrote some poems.
His mother and father met after Bran and Sceolang, two of his father's hounds, refused to kill a deer which they had captured.  
Oisin or Ossian