This name was common in Sweden and Denmark in the 1970s [1]. It rose in popularity in the English-speaking world in the 1990s, entering the top ten for girls in the United States in 2009. It was also popular in many other countries at that time. Famous bearers include American actress Mia Farrow (1945-) and American soccer player Mia Hamm (1972-), birth names Maria and Mariel respectively.
This was the name of a 13th-century Italian saint who made clothes for the poor. As an English name, it has never been common.
This name was brought to public attention after actors Angelina Jolie and Brad Pitt gave it to their daughter in 2006.