A king who lived in the beginning of this present age.
The Pāli Chronicles (Mhv.ii.1ff.; Dpv.iii.1ff.; MT. 122ff.; also J.ii.311; iii.454, etc.) mention him as the original ancestor of the Sākiyan family, to which the Buddha belonged, and gives a list of the dynasties from his day to the time of the Buddha, to prove that the line was "unbroken."
Mahāsammata belonged to the Solar Race and is identified with the Bodhisatta, who was born among men after sojourn in the Brahma worlds (MT. 121 f). He was called Mahāsammata, because, on the arising of wickedness in the world, he was chosen by the people (sannipatitvā samaggajātehi mahājanchi sammannitvā kato Mahāsammato; MT.122; cp. D.iii.92f.; Mtu.i.248; DhSA. 390, 392) to show indignation against and disapproval of those worthy of blame. In return for his services, he was given a portion of their harvest.
It is said (J.iv.192) that in the dynasty of Mahāsammata the idea of meting out punishments, such as torture, fining, expulsion, was unknown. These were invented later with the advance of civilisation!
The Vimānavatthu Commentary (p.15) explains that Mahāsammata is the name given in the sacred books (sāsane) for Manu.
Some, at least, of the Ceylon kings traced their descent from Mahāsammata. See, e.g., Cv.xlvii.2.