Potamius of Lisbon

Potamius is the earliest bishop of Lisbon whose name is recorded. He was in office by the middle of the 350s and appears in the sources for about a decade; he died sometime between 360 and 384. Everything known about him comes from the writings of his opponents and from the handful of his own texts that survived.

He walks into history at the worst possible moment. The emperor Constantius II was pressing the Western bishops to abandon the Nicene position, that the Son is of one substance with the Father, and to accept a vaguer formula that would satisfy the Eastern Arian party. The pressure came to a head at Sirmium in 357, at a gathering whose creed forbade the use of the word substance altogether, on the ground that it was not in Scripture and that human beings could not know how the Son was begotten.

Hilary of Poitiers, who fought that document for the rest of his life, called it the Blasphemy of Sirmium, and named Potamius of Lisbon as one of its authors. Phoebadius of Agen, another Gallic bishop, wrote a treatise against it and quoted Potamius directly. The Spanish bishop had gone over, and the Nicene party in the West never forgot it.

The sources disagree about what came after. Some later notices say he had earlier been orthodox and was bought, that Constantius gave him an imperial estate, and others report that he repented and returned to the Nicene confession before he died. The record is thin enough that both accounts have been argued.

A small body of his writing survives, and it is odd and vivid. Two short treatises come down among the works of Zeno of Verona: De Lazaro, on the raising of Lazarus, and De martyrio Isaiae prophetae, on the tradition that the prophet Isaiah was sawn in two. Both are written in strange, overheated Latin, thick with physical detail, the decay of Lazarus's body in the tomb described at length, the saw going through the prophet's flesh, a style unlike anything else from fourth-century Spain.

There is also a letter addressed to Athanasius, professing the Nicene faith, and a doctrinal letter on the substance of the Father, the Son, and the Holy Spirit, which reads as Nicene. Which of these came before the collapse at Sirmium and which after is exactly the question scholars cannot settle.

He is remembered chiefly because he shows how the Arian crisis worked at the edges of the empire: not as a debate among theologians in council chambers, but as pressure applied to a provincial bishop a long way from anywhere, who gave way, and whose name was written down for it.

Sources: Hilary of Poitiers, De synodis and the Fragmenta historica; Phoebadius of Agen, Contra Arianos; Marco Conti, The Life and Works of Potamius of Lisbon (Instrumenta Patristica, 1998); the 1913 Catholic Encyclopedia.