The name Maitreya (Metteyya in Pāli) is derived from the Sanskrit word maitrī (Pāli: mettā) meaning "loving-kindness", which is in turn derived from the noun mitra (Pāli: mitta) in the sense of "friend".
The earliest mention of Metteyya is in the Cakavatti (Sihanada) Sutta in the Digha Nikaya 26 of the Pali Canon. He occurs in no other sutta in the Pali Canon, and this casts doubt as to the sutta's authenticity. Most of the Buddha's sermons are presented as preached in answer to a question, or in some other appropriate context, but this one has a beginning and an ending in which the Buddha is talking to monks about something totally different. This leads Gombrich to conclude that either whole sutta is apocryphal, or it has at least been tampered with.
Maitreya is sometimes represented seated on a throne Western-style, and venerated both in Mahāyāna and non-Mahāyāna Buddhism. Some have speculated that inspiration for Maitreya may have come from the ancient Indo-Iranian deity Mithra. The primary comparison between the two characters appears to be the similarity of their names. According to a book entitled The Religion of the Iranian Peoples, "No one who has studied the Zoroastrian doctrine of the Saoshyants or the coming saviour-prophets can fail to see their resemblance to the future Maitreya.
Paul Williams claims that some Zoroastrian ideas like Saoshyant influenced the beliefs about Maitreya, such as "expectations of a heavenly helper, the need to opt for positive righteousness, the future millennium, and universal salvation". Possible objections are that these characteristics are not unique to Zoroastrianism, nor are they necessarily characteristic of the belief in Maitreya.
In the Greco-Buddhist art of Gandhara, in the first centuries CE in northern India, Maitreya was the most popular figure to be represented, together with the Buddha Śākyamuni. In China, in the 4th–6th Centuries "Buddhist artisans used the names Shakyamuni and Maitreya interchangeably... indicating both that the distinction between the two had not yet been drawn and that their respective iconographies had not yet been firmly set" An example is the stone sculpture found in the Qingzhou cache dedicated to Maitreya in 529 CE as recorded in the inscription (currently in the Qingzhou Museum, Shandong). The cult of Maitreya apparently developed around the same time of that of Amitābha, as early as the 3rd century CE.
Maitreya (Sanskrit), Metteyya (Pāli), or Jampa (Tibetan), is foretold as a future Buddha of this world in Buddhist eschatology. In some Buddhist literature, such as the Amitabha Sutra and the Lotus Sutra, he or she is referred to as Ajita Bodhisattva.
Maitreya is a bodhisattva who in the Buddhist tradition is to appear on Earth, achieve complete enlightenment, and teach the pure dharma. According to scriptures, Maitreya will be a successor of the historic Śākyamuni Buddha. The prophecy of the arrival of Maitreya references a time when the Dharma will have been forgotten on Jambudvipa. It is found in the canonical literature of all Buddhist sects (Theravāda, Mahāyāna, Vajrayāna), and is accepted by most Buddhists as a statement about an event that will take place when the Dharma will have been forgotten on Earth.