Pius I was the bishop of Rome from c. 140 to his death c. 154, according to the Annuario Pontificio. His dates are listed as 142 or 146 to 157 or 161, respectively. He is considered to have opposed both the Valentinians and Gnostics during his papacy. He is considered a saint by the Catholic Church and the Eastern Orthodox Church with a feast day in 11 July, but it is unclear if he died as a martyr.

Aquileia is an ancient Roman city in Italy, at the head of the Adriatic at the edge of the lagoons, about 10 kilometres (6 mi) from the sea, on the river Natiso, the course of which has changed somewhat since Roman times. Today, the city is small, but it was large and prominent in classical antiquity as one of the world's largest cities with a population of 100,000 in the 2nd century AD and is one of the main archaeological sites of northern Italy. In late antiquity the city was the first city in the Italian Peninsula to be sacked by Attila the Hun.