Justus m. Latin justus 'just, fair'.
The byname of a Biblical character who was later venerated as a saint, a 2nd C pope and saint, a semi-legendary 3rd C saint, two 4th C martyrs, a 4th C French saint, and a 6th C Spanish saint. Wycliffite Bible (1395): Just.
This name is sometimes conflated with Josse, via spellings such as Jost.