This was a common name in classical Greece, and, due to both the saints who carried it and the favourable meaning, it came into general use in the Christian world, being especially popular among Eastern Christians. It was however rare in Britain before the 19th century. Famous bearers include three tsars of Russia (in the Russian form Fyodor) and American president Theodore Roosevelt (1858-1919).
Very rare as an American given name before 1980, it increased in popularity in the 1980s and 90s. It got a boost in 2004 after the debut of the television series Lost, which featured a character by this name.
In the English-speaking world this name has been occasionally given since the early 20th century. It started rising in America after the variant Lorelai was used for the main character (and her daughter, nicknamed Rory) on the television series Gilmore Girls (2000-2007).
Famous bearers include the Welsh poet Dylan Thomas (1914-1953) and the American musician Bob Dylan (1941-), real name Robert Zimmerman, who took his stage surname from the poet's given name. Due to those two bearers, use of the name has spread outside of Wales in the last half of the 20th century. It received a further boost in popularity in the 1990s due to a character on the television series Beverly Hills 90210.
In America, this name received boosts in popularity from main characters in the movies The Jackal (1997) and Leap Year (2010).
This name experienced a rise in popularity at the end of the 20th century. It was the most popular name for girls in England and Wales from 2011 to 2015.