Saint Septimius of Iesi (Italian: Settimio di Jesi) (d. 307) was the first bishop of Iesi, a martyr and a saint.
Septimius was born in Germany, and after an education in the liberal arts began a military career. On his conversion to Christianity he parted from his family, who did not convert, and went to Italy, where he preached in Milan. He was forced to leave during the Persecution of Diocletian in 303. He later made his way to Rome, where the miracles he performed so impressed Pope Marcellus I that he created Septimius bishop of Iesi.
Septimius established Iesi Cathedral but was opposed by the local magistrate Florentius, who, after Septimius refused to sacrifice to the pagan gods, had him decapitated.
The body was re-discovered in 1469, although the cult of Septimius dated from much earlier, and translated to the cathedral, where a new altar was consecrated to the saint in 1623.
The saint's feast day was on 5 September until 1623, when it was changed to 22 September. Septimius is the patron saint of Iesi.
Iesi (Italian: Jesi [ˈjɛːzi]) is a town and comune of the province of Ancona in Marche, Italy.
It is an important industrial and artistic center in the floodplain on the left (north) bank of the Esino river 17 kilometres (11 mi) before its mouth on the Adriatic Sea.
Jesi was one of the last towns of the Umbri when, in the 4th century BC, the Senones Gauls invaded the area and ousted them. They turned it into a stronghold against the Piceni. In 283 BC the Senones were defeated by the Romans. Jesi in 247 BC became a colonia civium romanorum with the name of Aesis.
During the fall of the Western Roman Empire, Iesi was ravaged by the troops of Odoacer (476 AD) and again in 493 by the Ostrogoths of Theodoric the Great. After the Gothic War, Italy became part of the Byzantine Empire, and Jesi became one of the main centers of the new rulers, and also became a diocese seat. In 751 it was sacked by the Lombard troops of Aistulf, and later was a Carolingian imperial city.
Starting from 1130, it was an independent commune, gradually expanding in the neighboring countryside. In December 1194 it was the site of the birth of Holy Roman Emperor Frederick II, who later gave it the title of "Royal City". In the 14th century it was captured by the Papal vicar Filippo Simonetti, by Galeotto I Malatesta (1347–1351), by Braccio da Montone in 1408, and by Francesco I Sforza, who turned it into his family's main stronghold in the Marche. In 1447 it was bought by the Papal States.