manneredmannered

Mannered comes from Anglo-Norman manere, from Late Latin manuarius ‘of or pertaining to the hand’, and ultimately from Proto-Italic *manus.

1. Proto-Italicc. 1500–700 BCE*manus¹‘hand’reconstructed
2. Latinc. 75 BCE–200 CEmanus¹‘hand’
3. Late Latinc. 200–600 CEmanuarius²‘of or pertaining to the hand’
4. Late Latinc. 200–600 CEmanuāria²
5. Anglo-Normanc. 1066–1400manere²
6. Middle Englishc. 1150–1500manere³‘characteristics, manner’
7. Middle Englishc. 1150–1500manered⁴‘Possessing a specific disposition or behaviour’
8. Englishearliest quotation 2000mannered⁴

1. ¹ Wiktionary, Latin manuarius
2. ² Wiktionary, Middle English manere
3. ³ Wiktionary, Middle English manered
4. ⁴ Wiktionary, English mannered
5. Earliest quotation in Wiktionary’s entry: 2000, Richard W. Kaeuper, Violence in Medieval Society: “I doubt in general whether highly mannered societies are…”.

Earlier history uncertain. See Wiktionary.