Now don’t get all excited, but today is the Commemoration of St. Silas.
In the Martyrologium Romanum we read
3. Commemoratio sancti Silae, qui, ab Apostolis ad Ecclesias gentium una cum sanctis Paulo et Barnaba destinatus, praedicationis officium, gratia Dei plenus, instanter consummavit. … The commemoration of Saint Silas, who sent by the Apostles for the Churches of the gentiles together with Saints Paul and Barnabas, filled with the grace of God zealously fulfilled the duty of preaching.
See? It has nothing to do with Opus Dei.
Today we have an Old Testament figure as well:
2. Commemoratio sancti Esdrae, sacerdotis et scribae, qui, tempore Arataxeris regis Persarum, Babylone in Iudaeam rediens populum dispersum congregavit et omni studio enisus est, ut legem Domini investigaret, impleret et doceret in Israel.
I will let someone else try his hand at this second one! And it is well worth it!