Sextus Pompeius Maximus, 'father of the fathers'. Apparently he was the leader of the cult of Mithras in Ostia. We also learn that he was in charge of one of Ostia's ferry services.
Other brothers from Ostia
This plaque, now on display in the British Museum, may have come from the Aldobrandini Mithraeum in Ostia.
SEX POMPEIO SEX FIL / MAXIMO / SACERDOTI SOLIS IN / VICTI MT PATRI PATRVM / QQ CORP TREIECT TOGA / TENSIVM SACERDO / TES SOLIS INVICTI MT / OB AMOREM ET MERI /TA EIVS SEMPER HA / BET
Dedicated to Sextus Pompeius Maximus, son of Sextus, High Priest of the Sun God, Mithras, all powerful, and Father of Fathers, President of the Guild of Master Ferrymen. We, Priests of the all powerful Sun God, Mithras, do this on account of the high regard and affection we hold for him and his worthy deeds.