Family

She is mentioned in the "Letter To The Senate And People of Athens" by Julian the Apostate

Julian the Apostate

Julian "the Apostate" , commonly known as Julian, or also Julian the Philosopher, was Roman Emperor from 361 to 363 and a noted philosopher and Greek writer....

 to have been a sister of Constantius Gallus

Constantius Gallus

Flavius Claudius Constantius Gallus , commonly known as Constantius Gallus, was a member of the Constantinian dynasty and Caesar of the Roman Empire . Gallus was consul three years, from 352 to 354.- Family :...

. When mentioning the execution of Gallus by orders of Constantius II, Julian lists the several ways the two men were related. "Constantius gave over to his most inveterate enemies, his own cousin, the Caesar

Caesar (title)

Caesar is a title of imperial character. It derives from the cognomen of Julius Caesar, the Roman dictator...

, his sister

Constantina

Constantina , and later known as Saint Constance, was the eldest daughter of Roman Emperor Constantine the Great and his second wife Fausta, daughter of Emperor Maximian...

's husband, the father of his niece, the man whose own sister he had himself married in earlier days".

Gallus was a son of Julius Constantius

Julius Constantius

Julius Constantius was a politician of the Roman Empire and a member of the Constantinian dynasty, being a son of emperor Constantius Chlorus and his second wife Flavia Maximiana Theodora, a younger half-brother of emperor Constantine I and the father of emperor Julian.- Biography :Julius...

 and his first wife Galla

Galla (wife of Julius Constantius)

Galla was a member of the Constantinian dynasty that ruled on the Roman Empire.- Biography :Galla was the sister of the consul Neratius Cerealis and of the praetorian prefect Vulcacius Rufinus....

. She is assumed to be a full sister of Gallus. Julius Constantius was a son of Constantius Chlorus

Constantius Chlorus

Constantius I , commonly known as Constantius Chlorus, was Roman Emperor from 293 to 306. He was the father of Constantine the Great and founder of the Constantinian dynasty. As Caesar he defeated the usurper Allectus in Britain and campaigned extensively along the Rhine frontier, defeating the...

 and Flavia Maximiana Theodora

Flavia Maximiana Theodora

Flavia Maximiana Theodora was the stepdaughter of Maximian. Her parents were Flavius Afranius Hannibalianus and wife, divorced before 283, Eutropia, later wife of Maximian. Theodora's father was consul in 292, and praetorian prefect under Diocletian...

. He was a paternal half-brother of Constantine I

Constantine I

Constantine the Great , also known as Constantine I or Saint Constantine, was Roman Emperor from 306 to 337. Well known for being the first Roman emperor to convert to Christianity, Constantine and co-Emperor Licinius issued the Edict of Milan in 313, which proclaimed religious tolerance of all...

. In 337, Constantine I died. Several of his relatives were killed shortly after his death. Julius Constantius was among them. The "History of the Arians" (358) by Athanasius of Alexandria

Athanasius of Alexandria

Athanasius of Alexandria [b. ca. – d. 2 May 373] is also given the titles St. Athanasius the Great, St. Athanasius I of Alexandria, St Athanasius the Confessor and St Athanasius the Apostolic. He was the 20th bishop of Alexandria. His long episcopate lasted 45 years Athanasius of Alexandria [b....

 reports on Constantius II having killed his father-in-law. Though Constantius had two later marriages, this is considered a reference to Julius Constantius. "The common feelings of humanity could not induce him to spare even his own kindred. His uncles he slew; his cousins he put out of the way; he commiserated not the sufferings of his father-in-law, though he had married his daughter, or of his kinsmen".

A brother is considered to have been assassinated with their father in 337. Julian the Apostate was a younger, paternal half-brother to this Empress.

Marriage

Her marriage to Constantius seems to be recorded in the Life of Constantine by Eusebius of Caesarea

Eusebius of Caesarea

Eusebius of Caesarea also called Eusebius Pamphili, was a Roman historian, exegete and Christian polemicist. He became the Bishop of Caesarea in Palestine about the year 314. Together with Pamphilus, he was a scholar of the Biblical canon...

. "On the completion of the thirtieth year of his [Constantine's] reign he solemnized the marriage of his second son [Constantius II], having concluded that of his first-born long before. This was an occasion of great joy and festivity, the emperor himself attending on his son at the ceremony, and entertaining the guests of both sexes, the men and women in distinct and separate companies, with sumptuous hospitality. Rich presents likewise were liberally distributed among the cities and people." The marriage can be estimated to 335 or 336. Constantine I had been declared emperor in 306.

Neither her name nor the time of her death appear in surviving sources. Thomas M. Banchich , a modern historian, points that "her passing may have facilitated Gallus' fall in 353/4". The "Panegyric In Honour Of Eusebia" by Julian the Apostate places the marriage of Eusebia

Eusebia (empress)

Eusebia was the second wife of Emperor Constantius II. Main sources for the knowledge about her life are Julian's panegyric "Speech of Thanks to the Empress Eusebia" in which he thanks her for her assistance, as well as several remarks by the historian Ammianus Marcellinus.-Family:The primary...

, second wife of Constantius, prior to the defeat of rival emperor Magnentius

Magnentius

Flavius Magnus Magnentius was a usurper of the Roman Empire .-Early life and career:...

. Magnentius was dead by August, 353. The marriage of Constantius and Eusebia may have occurred earlier in the year.