|Reign||c. June – July 251|
|Predecessor||Decius and Herennius Etruscus|
|Successor||Trebonianus Gallus and Volusianus|
|Died||c. July 251|
Hostilian (Latin: Gaius Valens Hostilianus Messius Quintus; died 251) was briefly Roman emperor in 251. Hostilian was born to Decius and Herennia Etruscilla at an unknown date and elevated to caesar in 250 by Decius. After Decius and Herennius Etruscus, Hostilian's brother, were killed at the Battle of Abritus, an ambush by the Goths, Trebonianus Gallus was proclaimed emperor by the legions. Almost immediately, he elevated Hostilian to co-emperor and his own son, Volusianus, to caesar. Hostilian died soon after, either due to plague or being murdered by Trebonianus Gallus.
Hostilian was born at an unknown date, to Decius, a Roman general who later became Emperor, and his wife Herennia Etruscilla. He had a brother, Herennius Etruscus and one sister. His full name based on coinage and inscriptions was Gaius Valens Hostilianus Messius Quintus but the historian Aurelius Victor also provides him with another nomen Perpenna or Perperna, a name of Etruscan origin.
Decius became emperor after being sent to lead troops in the provinces of Pannonia and Moesia, where he was declared emperor by his troops in September 249, in opposition to Philip the Arab. He led his troops against Philip, their forces meeting in September 249, near Verona, Italy. Philip was killed in battle, after which the Roman Senate declared Decius emperor and honoured him with the name Traianus, a reference to Emperor Trajan.
Hostilian was elevated to caesar in 250, probably in September, by his father Decius. The elevation came after the promotion of his older brother, Herennius Etruscus, to augustus in the same month, making Herennius Etruscus co-emperor, with Hostilian as the heir of either or both of them. After Decius and Herennius Etruscus were killed by the Goths at the Battle of Abritus, Trebonianus Gallus was declared emperor. To placate the public, Trebonianus Gallus elevated Hostilian to augustus almost immediately, making him co-emperor. Hostilian was co-emperor until his death in July 251; the reason for his death is disputed. His death is sometimes dated to November, but contemporary sources indicate that he died on or before August, probably in July. Aurelius Victor and the author of the Epitome de Caesaribus say that Hostilian died of a plague. Zosimus claims that he was killed by Trebonianus Gallus. After his death, Trebonianus Gallus made Volusianus, his son, co-emperor.
Some historians identify Hostilian as the Roman general depicted in the Ludovisi Battle sarcophagus, but this is unlikely given that all of his coins depict him as a beardless young boy. It's possible that both Hostilian and Herennius Etruscus were still children or teenagers at the moment of their death.
The aurei of Hostilian fall into four types bearing the bust of Hostilian on the obverse, with the reverse showing: Mars walking to the right; priestly implements; Mercury standing; and Roma seated holding Victoria.