Oisín, along with st. Patrick, is the main character of william butler yeats's epic poem the wanderings of oisin. He is also mentioned in yeats's poem the circus animals' desertion.

See sadb and the birth of oisín in the fenian cycle. One tale tells of how he and caílte mac ronan survived … Oisín mounted niamh's magical white horse, embarr, and together they crossed the seas to tír na nóg. In this otherworldly land, time flowed differently, and no one aged or died. Oisín and niamh lived …

Oisín and niamh lived …