The story
- Latin · derived fromimperātorem
- Anglo-Norman · derived fromemperour
- Middle English · inherited fromemperour
- English todayemperor
From Middle English emperour, from Anglo-Norman emperour, from Latin imperātorem, derived from imperō (“to command”). Doublet of imperator. Displaced earlier Old English casere, from Latin Caesar.
Etymology from Wiktionary, CC BY-SA 4.0.