'ancienter' is formed from the adjective 'ancient' with the comparative suffix '-er', following the pattern of English comparatives.

'Ancient' comes from Middle English 'auncien', from Old French 'ancien', from Latin 'anteanus', meaning 'former' or 'old'. The comparative 'ancienter' is a rare, archaic form.

Initially, 'ancient' meant 'former' or 'old', and 'ancienter' simply meant 'more old'. Over time, 'ancienter' fell out of common usage, replaced by 'more ancient'.