Yours, Etc.: Origins and Uses of 8 Sign-Offs
Old English awæcnan (intransitive), "to spring into being, arise, originate," also, less often, "to wake up;" earlier onwæcnan, from a- (1) "on" + wæcnan (see waken). Transitive meaning "to rouse from sleep" is recorded from 1510s; figurative sense of "to stir up, rouse to activity" is from c.1600.
Originally strong declension (past tense awoc, past participle awacen), already in Old English it was confused with awake (v.) and a weak past tense awæcnede (modern awakened) emerged and has since become the accepted form, with awoke and awoken transferred to awake. Subtle shades of distinction determine the use of awake or awaken in modern English. Related: Awakening.