They began to become common during the end of the middle ages (or the early modern period depending on whom you ask). The region is that as populations started to grow, you needed double names to be distinct, especially since people seem to have a preference for a very limited number of names (in the gemara period, people used far more names).. According to one of the early bibliographies of sefarim, published in Amsterdam in the late 18th century, Ashkenazi custom was to call a person by the second name, and Sefardi custom was to call someone by the first, but these are generalizations.
Given that surnames (family names) are now used, and pioneered by the Jews in Eretz Yisrael, many people are using a wider variety of personal names, it will be interesting if the use of having multiple forenames (personal names) will continue.