Where does “Tranquillus” come from?
Tranquillus (Latin) comes from Latin trānsquīlus, from Latin quiēs, from Proto-Italic kʷiētis, from Proto-Indo-European kʷyéh₁tis, from Proto-Indo-European kʷyeh₁- — to rest; rest, peace.
Ancestry of “Tranquillus”, step by step