Theodor von Sitten

Theodore of Octodurum, known in German as Theodor von Sitten and in French as Théodore d'Octodure or Théodore de Sion, was a fourth-century Christian bishop and the earliest bishop of Octodurum who can be treated as a historical figure. Octodurum was a Roman settlement at the foot of the Great Saint Bernard Pass and corresponds to modern Martigny in the Swiss canton of Valais. Almost nothing can be verified about his birth, parentage, education, or early career. Later medieval legends sometimes describe him as a man of Eastern or Greek origin, but those claims lack contemporary corroboration and should not be treated as fact. His episcopate belongs to the later fourth century, in the generation that followed the legalization of Christianity in the Roman Empire and that saw dioceses organized in the western Alpine provinces.

The principal ancient testimony to his activity is the account of the martyrs of Agaunum written by Eucherius, bishop of Lyon, around the middle of the fifth century. Eucherius records that Theodore, bishop of Octodurum, discovered the remains of the Theban Legion—Saint Maurice and his companions—believed to have been killed at Agaunum (present-day Saint-Maurice) for refusing pagan rites. According to this tradition Theodore gathered the relics and caused a basilica to be built over their tombs. That sanctuary became the nucleus of the Abbey of Saint-Maurice, among the oldest continuously occupied monastic houses in Europe. Whether Theodore himself founded a clerical community there cannot be confirmed from fourth-century sources, but his name remained inseparably linked to the Theban martyrs in later cult and legend.

In the sixth century the episcopal seat was transferred from Octodurum up the Rhône valley to Sedunum, the present city of Sion (German: Sitten). Theodore's relics were translated to the new cathedral city, and he was thereafter venerated as founder-bishop and patron of the Diocese of Sion. Medieval bishops of Sion presented themselves as his successors, and his memory was bound to the identity of the church in the Valais. He is commonly shown in art as a bishop, sometimes with a model of a church or in association with the Theban Legion. His feast is kept on 16 August, especially in the Diocese of Sion and in the canton of Valais.

Because the surviving evidence is late and largely hagiographical, the precise year of his death, the place of his original burial, and the details of his pastoral work cannot be established with certainty. No authentic writings of his own are known, and his name does not appear in the securely dated lists of participants at the major Western councils of the late fourth century in a form that all historians accept without reservation. What can be said is that a bishop named Theodore of Octodurum was remembered within a few generations as the discoverer of the Agaunum martyrs and as the first notable shepherd of the church in the Valais, and that an ancient cult, centered first at Martigny and Agaunum and later at Sion, has preserved his name as Theodor von Sitten.