Messenius
Could not find Messenii in Logeion dictionaries.
Messenii proper-name adjective masculine vocative plural, proper-name adjective neuter genitive singular, proper-name adjective masculine nominative plural, proper-name adjective masculine genitive singular of Messenius
1. Messēnius, s. Messāna.
2. Messēnius, s. Messēnia.
Messēnĭus, a, um (Μεσσήνιος), de Messène ou de Messine : Ov. M. 2, 679 || Messenii, les Messéniens : Liv. 36, 31.