Pali literature is concerned mainly with Theravada Buddhism, of which Pali is the traditional language. The earliest and most important Pali literature constitutes the Pāli Canon, the authoritative scriptures of Theravada school. Pali literature includes numerous genres, including Suttas (Buddhist discourses), Vinaya (monastic discipline), Abhidhamma (philosophy), poetry, history, philology, hagiography, scriptural exegesis, and meditation manuals. The Pali language is a composite language which draws on various Middle Indo-Aryan languages. Much of the extant Pali literature is from Sri Lanka, which became the headquarters of Theravada for centuries. Most extant Pali literature was written and composed there, though some was also produced in outposts in South India. Most of the oldest collection of Pali Literature, the Pali Canon, was committed to writing in Sri Lanka at about the first century BCE (though it contains material that is much older, possibly dating to the period of pre-sectarian Buddhism). At around the start of the common era, some of the earliest Pali commentaries and exegetical manuals (which are now sometimes included within the Pali Canon itself) were written, mainly the Suttavibhanga, Niddesa, Nettipakarana and Petakopadesa. Other works like the Cariyapitaka, the Buddhavamsa and the Apadana may also belong to this post-Asokan period. During the first millennium, Pali literature consisted of two major genres: histories (vamsa) and commentaries (atthakatha). The histories include the Dipavamsa and the Mahavamsa, which are verse chronicles of Buddhism in India and Sri Lanka. The commentarial works include the writings of Buddhaghosa (4th or 5th century CE), who wrote the influential Visuddhimagga along with various commentaries on the Pali Canon. Several other commentators worked after Buddhaghosa, such as Buddhadatta (c. fifth century), Ananda (sixth century), Dhammapala (at some point before the 12th century) and other anonymous commentators which we do not know by name.