All active servers in Final Fantasy XI are named after summons from earlier entries in the series. Some servers employed during the game's beta tests were named after enemies instead. Final Fantasy XI launched with twenty servers available for public use and subsequently added another fifteen. Nineteen sparsely populated servers have since been decommissioned, however, leaving the game with its current roster of sixteen. Characters on discontinued worlds were automatically transferred to other servers.
In addition to the servers listed below, worlds named Chocobo and Moogle have been used for special events and product demonstrations. Game data also specifies the existence of Behemoth, Dragon, Chimera, and Wyvern servers whose intended purposes are unknown.
All of the servers in Final Fantasy XIV are named after famous weapons from the Final Fantasy series. The chosen weapons are all prominent weapons from the game of origin of one of the previous server names (example Wutai + Gysahl => Masamune), and are related to mythology.
Previously, they were named after towns, but this will was changed after March 2012's server merge, due to the plan of including content based after previous games in the series - which could include naming one such content after a previous game town, for example - as well as preventing players from congregating on a single server due to it's name - with "Midgar" being used as an example of a possible server name that could become overcrowded simply due to it's name.
Test servers were named after previous Final Fantasy villains, and two internal servers called Zvahl and Narshe are closed to the public. Some of the release servers were also activated during Beta.
Servers used in the Alpha test for Final Fantasy XIV: A Realm Reborn began with Moogle and Chocobo, with the later addition of Bahamut. Moogle and Chocobo were later merged, the new server named Louisoix. The use of these names vaguely summarizes the end of the Seventh Umbral Era, particularly the clash between Bahamut and Louisoix.