Mahāvastu

A lengthy composite work, the earliest sections of which go back to the 2nd century bce. The text incorporates many early short sūtras and Jātakas, structured around a core biography of the Buddha said to have been a work attached to the Vinaya of the Lokottara-vāda school. The text also appears to contain later material, including substantial intrusions from Mahāyāna. The work only survives in a manuscript written in a form of Sanskrit known as Buddhist Hybrid Sanskrit, and no translations are available in either Tibetan or Chinese.

A Dictionary of Buddhism, Oxford University Press, 2003, 2004 (which is available in electronic version from answer.com)