Examples: cartography card archaeology archetype monarchy legal loyal purse personal cinema kinase car carpenter hippopotamus Mesopotamia dative data date
...
Middle English -ere

→ English -er (mention)
→ English -er (mention)
→ English -er (inherited)
→ English -er (mention)
→ English -ar (cognate)
→ English gilder (mention)
→ English defender (mention)
→ English astrologer (derived)