Hispania was the Roman name for the Iberian Peninsula. Under the Republic, Hispania was divided into two provinces: Hispania Citerior and Hispania Ulterior. During the Principate, Hispania Ulterior was divided into two new provinces, Baetica and Lusitania, while Hispania Citerior was renamed Tarraconensis. Subsequently, the western part of Tarraconensis was split off, first as Hispania Nova, later renamed Callaecia (or Gallaecia, whence modern Galicia). From Diocletian's Tetrarchy (AD 284) onwards, the south of remaining Tarraconensis was again split off as Carthaginensis, and probably then too the Balearic Islands and all the resulting provinces formed one civil diocese under the vicarius for the Hispaniae (that is, the Celtic provinces). The name, Hispania, was also used in the period of Visigothic rule. The modern name Spain derives from Hispania.