The 300s decade ran from January 1, 300, to December 31, 309.
Year 303 (CCCIII) was a common year starting on Friday of the Julian calendar. It was known in the Roman Empire as the Year of the Consulship of Diocletian and Maximian. The denomination 303 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.
Erasmus of Formia, also known as Saint Elmo, was a Christian saint and martyr. He is venerated as the patron saint of sailors and abdominal pain. Erasmus or Elmo is also one of the Fourteen Holy Helpers, saintly figures of Christian religion who are venerated especially as intercessors.
Mediolanum, the ancient city where Milan now stands, was originally an Insubrian city, but afterwards became an important Roman city in Northern Italy.
May 7 - Eastern Orthodox Church calendar - May 9
Zeno of Verona was an Afro-Italian Christian figure believed to have either served as Bishop of Verona or died as a martyr. He is venerated as a saint in the Catholic Church and the Orthodox Church.
Gervasius and Protasius are venerated as Christian martyrs, probably of the 2nd century. They are the patron saints of Milan and of haymakers and are invoked for the discovery of thieves. Their feast day in the Latin Rite of the Catholic Church is 19 June, the day marking the translation of their relics. In the Eastern Orthodox Church and in the Eastern Rites of the Catholic Church, their feast takes place on 14 October (O.S.)/24 October (N.S.), the traditional day of their death. In Christian iconography their emblems are the scourge, the club and the sword.
Nabor and Felix were Christian martyrs thought to have been killed during the Great Persecution under the Roman emperor Diocletian. A tomb in Milan is believed to contain their relics.
Vitalis and Agricola are venerated as martyrs and saints, who are considered to have died at Bologna about 304, during the persecution ordered by Roman Emperor Diocletian.
Saints Firmus and Rusticus are venerated as two martyrs of Verona.
Gereon of Cologne, who may have been a soldier, was martyred at Cologne by beheading, probably in the early 4th century.
The Basilica of Sant'Ambrogio is an ancient Romanesque-style, Roman Catholic church in the center of Milan, region of Lombardy, Italy.
Saint Marcellus of Tangier or Saint Marcellus the Centurion was a Roman centurion who is today venerated as a martyr-saint in both the Eastern Orthodox and the Catholic Church. His feast day is celebrated on October 30.
Alexander of Bergamo is the patron saint of Bergamo, as well as Capriate San Gervasio and Cervignano d'Adda. Alexander may have been a Roman soldier or resident of Bergamo who was tortured and killed for not renouncing his Christian faith. Details of his life are uncertain, but subsequent Christian stories consider him a centurion of the Theban Legion commanded by Maurice.
Fidelis of Como was an Italian soldier-saint, according to Christian tradition.
Maternus was Archbishop of Milan from c. 316 to c. 328. He is honoured as a Saint in the Catholic Church and his feast day is on July 18.
The Oratorio di San Protaso is a church in via Lorenteggio, Milan, Lombardy.
Early Christian churches in Milan are the first churches built immediately after the Edict of Milan in February 313, issued by Constantine the Great and Licinius, which granted tolerance and religious liberty to Christianity within the Roman Empire.
Mirocles was Bishop of Milan from before 313 to c. 316. He is honoured as a Saint in the Catholic Church and his feast day is on December 3.
The church and monastery of San Vittore al Corpo were an ancient monastery of the Olivetan order built in the early 16th century. The site was once a fourth century Roman imperial mausoleum of Maximian, that may also have held the burials of the emperors Gratian and Valentinian II, though they were more likely buried in another mausoleum, now the Chapel of Saint Aquilinus in the Basilica of Saint Lawrence. The basilica was enlarged in the 8th century to house the relics of the saints Vittore and Satiro. A Benedictine monastery soon was attached to the church. In 1507, the monastery was transferred to the Olivetans, who began a major reconstruction. Reconstruction of the church was begun in 1533 by Vincenzo Seregni, and completed in 1568 by Pellegrino Tibaldi. The façade remains incomplete. The dome was frescoed in 1617 by Guglielmo Caccia. In the chapel of St Anthony is a 1619 canvas by Daniele Crespi. In the transept on the left, is an early 17th-century cycle of canvases of the Stories of San Benedetto, by Ambrogio Figino while the right transept has three altarpieces by Camillo Procaccini. Other chapels have paintings by Pompeo Batoni and Giovanni Battista Discepoli.
