The There Will Be Blood star and his sister Tamasin handed the collection to Oxford's Bodleian Libraries, the largest university library system in the U.K.
The files include the final stanza of The Newborn, written to mark Daniel's birth in 1957, as well as a letter from fellow poet W.H. Auden to Cecil criticising one of the latter's poems.
A statement from the Day-Lewis siblings reads, ""If the manuscripts had ended up outside the country it would have saddened us all as a family as the poets who became papa's lifelong friends and peers all met up at Oxford as undergraduates.""
Oxford heads have organised a day of special events on Tuesday (30Oct12) to mark the donation.
Cecil studied Classics at Oxford's Wadham College, and went on to become a professor of poetry there in 1951. He was appointed Poet Laureate of the U.K. in 1968.