A letter from Mr. [Brian Houghton] Hodgson to Mr. Bayley, was then read, giving an outline of the theocracy of the Buddha system of Nepal. […] According to the information now communicated, the northern Buddhas acknowledge four sets of divine beings, or of superhuman objects of veneration. The first of these is, contrary to the generally supposed atheistical tendency of the faith, one primæval and uncreated deity. This first Buddha manifested five of his attributes, as five secondary Buddhas; in one of whom, Amitabha, or the 'immeasurably splendid,' in Prakrit and Pali, Amitabo, we recognise the Amito of the Japanese.
Source: wiktionary