'ate' (past tense of 'eat') originates from Old English, specifically the word 'æt', where the base verb was 'etan' meaning 'to eat'.

'ate' changed from Old English past form 'æt' (from the verb 'etan') and eventually became the modern English past tense 'ate'.

Initially it meant simply the past action 'did eat'; this core meaning has remained largely the same into modern English.