Willie O Winsbury is Child Ballad 100 (Roud 64), existing in several variants. It is a traditional Scottish ballad that dates from at least 1775, and is known under a number of different names, including Lord Thomas of Winesberry.
A king is away for a long time. His daughter becomes pregnant by the hero, William or Thomas. The king threatens to hang him, but is struck by his beauty and offers him the heroine, gold, and land. The hero accepts the lady but declares the gold and the land to be his lady's, not his own.
This ballad closely parallels Child ballad 99, "Johnie Scot".
In one variant, the lands are specifically described: he will be king when he returns to Scotland. It may, in fact, be based on James V's courtship of and marriage to Madeleine de Valois of France; James came to see the woman he was betrothed to in disguise, and went on to meet the princess, who fell in love with him.
Nowadays the song is often sung to the tune of "Fause Foodrage", rather than its own traditional tune.
This song was first recorded by Sweeney's Men on their eponymous debut album in 1968, sung by Andy Irvine accompanying himself on guitar. At the time, Johnny Moynihan stated on the sleeve notes: "A ballad for which Andy is renowned. He got the text from Child's 'English and Scottish Ballads'; looking up the tune he got his numbers confused and emerged with the wrong air. By chance it suited the song very well". In 2010, Irvine re-recorded the song with a fuller arrangement of the same tune on his album Abocurragh, adding: "This is Child 100. I collected the words from different versions and as the story goes, on looking up the tune, I lighted on the tune to number 101. I'm not sure if this is true but it's a good story".
The song "Farewell, Farewell" recorded by Fairport Convention on their album Liege and Lief in 1969 features new lyrics (written by Richard Thompson) set to the "Fause Foodrage" tune now commonly used for "Willie O' Winsbury". A recording of "Willie O' Winsbury" played and sung by Thompson was included in his compilation boxset RT.