In the United States it became more common for girls in the early 1980s, shortly after the debut of the television sitcom The Facts of Life (1979-1988), which featured a character named Blair Warner. The name left the American top 1000 rankings two decades later, but was resurrected by another television character, this time Blair Waldorf from the series Gossip Girl (2007-2012).
It has been common as a given name in the English-speaking world only since the 18th century. A famous modern bearer is American actress Julia Roberts (1967-).
The name was very popular until the 15th century in England, usually in the vernacular form Maud. Both forms were revived by the 19th century. This name appears in the popular Australian folk song Waltzing Matilda, written in 1895.