However, according to a text in the Theravada Buddhist tradition from a later strata (between 1st and 2nd century BCE) called the Buddhavamsa, twenty-one more Buddhas were added to the list of seven names in the early texts. Theravada tradition maintains that there can be up to five Buddhas in a "kalpa" or world age and that the current "kalpa" has had four Buddhas, with the current Buddha, Gotama, being the fourth and the future Buddha Metteyya being the fifth and final Buddha of the "kalpa". This would make the current aeon a "bhadrakalpa" (fortunate aeon). In some Sanskrit and northern Buddhist traditions however, a "bhadrakalpa" has up to 1,000 Buddhas, with the Buddhas Gotama and Metteyya also being the fourth and fifth Buddhas of the "kalpa" respectively.