Perfect enlightenment long acquired; Śākya-Tathāgata in ancient kalpas having achieved complete bodhi, transmitted it to Mañjuśrī Avalokiteśvara, and others, i.e., their enlightenment is the fruit of his enlightenment. 法華經:壽量品.

A Dictionary of Chinese Buddhist Terms, William Edward Soothill and Lewis Hodous

久成正覺===（術語）謂久遠之昔既開正覺之果之佛體也。依法華經壽量品之意，則始於釋迦如來。而文殊觀音等大菩薩皆由久成古佛之垂跡也。輔行六曰：「遍尋法華以前諸教，實無二乘作佛之文明如來久成之說，故知並由帶方便故。」

丁福保《佛學大辭典》