Pope Saint Mark the apostle or Marcus was Pope

Pope

The Pope is the Bishop of Rome, a position that makes him the leader of the worldwide Catholic Church . In the Catholic Church, the Pope is regarded as the successor of Saint Peter, the Apostle...

 from January 18, 336 to October 7, 336, date of his death.

Little is known of his early life. According to the Liber Pontificalis

Liber Pontificalis

The Liber Pontificalis is a book of biographies of popes from Saint Peter until the 15th century. The original publication of the Liber Pontificalis stopped with Pope Adrian II or Pope Stephen V , but it was later supplemented in a different style until Pope Eugene IV and then Pope Pius II...

, he was a Roman, and his father's name was Priscus. Some evidence suggests that the early lists of bishops and martyrs known as the Depositio episcoporum and Depositio martyrum were begun during his pontificate. Mark also issued a constitution confirming the power of the bishop of Ostia

Bishop of Ostia

The Bishop of Ostia is the head of the Suburbicarian Diocese of Ostia, one of the seven suburbicarian sees of Rome. The position is now attached to the post of Dean of the College of Cardinals, as it has been since 1150, with the actual governance of the diocese entrusted to the Vicar General of...

 to consecrate newly elected popes. Mark is credited with the foundation of the basilica

Basilica

The Latin word basilica , was originally used to describe a Roman public building, usually located in the forum of a Roman town. Public basilicas began to appear in Hellenistic cities in the 2nd century BC.The term was also applied to buildings used for religious purposes...

 of San Marco in Rome, and a cemetery church over the Catacomb of Balbina, just outside the city.

Mark died of natural causes and was buried in the catacomb of Balbina

Balbina

Memorials of St. Balbina are to be found at Rome in three different spots which are connected with the early Christian antiquities of that city. In the purely legendary account of the martyrdom of St. Alexander mention is made of a tribune Quirinus who died a martyr and was buried in the catacomb...

, where he had built the cemetery church. His feast day is on October 7.