Abundius

Saint Abundius, known in Italian as Sant'Abbondio and also appearing in sources as Abondius or Abundias, was a bishop of Como in northern Italy in the fifth century. Hagiographical tradition records that he was born in Thessalonica. He became bishop of Como, regarded as the fourth occupant of that see after its founder Saint Felix and the subsequent bishops including Saint Amantius, around the middle of the fifth century.

During his episcopate the Church was engaged in the controversy over the nature of Christ that followed the condemnation of Eutyches. In 450 Pope Leo I sent Abundius to Constantinople as his legate. Abundius took part in a synod held there and was instructed to protest the installation of Anatolius as patriarch of Constantinople on account of the latter's Eutychian connections and to urge the calling of an ecumenical council. Traditional narratives also place him among the papal representatives at the Council of Chalcedon in 451, which produced the definition of the two natures of Christ united in one person.

Abundius returned to Como and remained its bishop until his death, which later sources date to 469. He was buried in the city. A church dedicated to him was built over his tomb; the existing Basilica of Sant'Abbondio, reconstructed in the Romanesque style in the eleventh century, occupies that location south of the historic center of Como and preserves his relics. His feast day is celebrated on 2 April.

Veneration of Abundius as a saint arose in the local church of Como and has continued without interruption. He is honored as the principal patron saint of Como and of its diocese. No contemporary vita survives, and information about his origins, the precise dates of his career, and the details of his pastoral work is therefore limited to later liturgical and hagiographical notices together with the indirect evidence of his reported role in the events of 450 and 451. Like many bishops of the period, he is known to history chiefly through his connection with the papacy of Leo the Great and the Christological councils of the mid-fifth century.