Gelasius of Caesarea was bishop of Caesarea Maritima from 367 to 373 and from 379 to his death. He was also an author, though none of his work survives.

Gelasius participated in the First Council of Constantinople

First Council of Constantinople

The First Council of Constantinople is recognized as the Second Ecumenical Council by the Assyrian Church of the East, the Oriental Orthodox, the Eastern Orthodox, the Roman Catholics, the Old Catholics, and a number of other Western Christian groups. It was the first Ecumenical Council held in...

 in 381. He was forced to surrender his position as bishop to the semi-Arian

Arian

Arian may refer to:* Arius, a Christian presbyter in the 3rd and 4th century* a given name in different cultures: Aria, Aryan or Arian...

ist Euzoius between the years of 373 and 379, because in matters of Christology

Christology

Christology is the field of study within Christian theology which is primarily concerned with the nature and person of Jesus Christ as recorded in the Canonical gospels and the letters of the New Testament. Primary considerations include the relationship of Jesus' nature and person with the nature...

 he was a staunch Nicaean

First Council of Nicaea

The First Council of Nicaea was a council of Christian bishops convened in Nicaea in Bithynia by the Roman Emperor Constantine I in AD 325...

.

According to Jerome

Jerome

Saint Jerome was a Roman Christian priest, confessor, theologian and historian, and who became a Doctor of the Church. He was the son of Eusebius, of the city of Stridon, which was on the border of Dalmatia and Pannonia...

, his writing was careful and polished, though he never published what he wrote. However, in the fifth century Socrates Scholasticus

Socrates Scholasticus

Socrates of Constantinople, also known as Socrates Scholasticus, not to be confused with the Greek philosopher Socrates, was a Greek Christian church historian, a contemporary of Sozomen and Theodoret, who used his work; he was born at Constantinople c. 380: the date of his death is unknown...

 cites some of his works, and it seems that he wrote a sequence to Eusebius' Church History

Church History (Eusebius)

The Church History of Eusebius, the bishop of Caesarea was a 4th-century pioneer work giving a chronological account of the development of Early Christianity from the 1st century to the 4th century. It was written in Koine Greek, and survives also in Latin, Syriac and Armenian manuscripts...

, preserved in the first fifteen chapter's of Rufinus

Tyrannius Rufinus

Tyrannius Rufinus or Rufinus of Aquileia was a monk, historian, and theologian. He is most known as a translator of Greek patristic material into Latin—especially the work of Origen.-Life:...

' tenth book added to Eusebius' history, which includes the legend of Helena's discovery of the True Cross

True Cross

The True Cross is the name for physical remnants which, by a Christian tradition, are believed to be from the cross upon which Jesus was crucified.According to post-Nicene historians, Socrates Scholasticus and others, the Empress Helena The True Cross is the name for physical remnants which, by a...

.

Gelasius was nephew to Cyril of Jerusalem

Cyril of Jerusalem

Cyril of Jerusalem was a distinguished theologian of the early Church . He is venerated as a saint by the Roman Catholic Church, the Eastern Orthodox Church, and the Anglican Communion. In 1883, Cyril was declared a Doctor of the Church by Pope Leo XIII...

, the most vigorous advocate for Jerusalem in the later fourth century, and at whose deathbed request Gelasius wrote his history.

He is also the first to mention the rôle of Helena, the mother of Constantine the Great, in the finding (inventio) of the Holy Wood, the Cross of Christ in Jerusalem under the Temple of Venus on the hill known as Golgotha.