'attester' originates from Latin, specifically the word 'attestari', where the prefix 'ad-' meant 'to' and 'testari' meant 'to witness'.

'attester' changed from Old French/Anglo-French 'attester' (from Latin 'attestari') and Middle English forms such as 'attesten', and eventually became the modern English noun 'attester'.

Initially, it meant 'to bear witness or declare truth' (in the verbal form), but over time it evolved into the current noun meaning 'a person who bears witness or certifies something'.