Predecessor
late Middle English: from late Latin praedecessor, from Latin prae ‘beforehand’ + decessor ‘retiring officer’ (from decedere ‘depart’).
wiktionary
From Middle English predecessour, from Old French predecesseor(“forebear”), from Late Latin praedēcessor, from Latin prae-(“pre-”) + Latin dēcessor(“retiring officer”), from Latin dēcēdō(“I retire, I die”) (English decease).
etymonline
predecessor (n.)
late 14c., predecessour, "one who has held an office or position before the present holder," from Old French predecesseor "forebear" and directly from Late Latin praedecessorem (nominative praedecessor) "one who has gone before," from Latin prae "before" (see pre-) + decessor "retiring official," from decess-, past participle stem of decedere "go away," also "die" (see decease (n.)). Meaning "ancestor, forefather" is recorded from c. 1400.