Honorius (9 September 384 – 15 August 423) was Roman emperor from 393 to 423. He was the younger son of emperor Theodosius I and his first wife Aelia Flaccilla. After the death of Theodosius in 395, Honorius, under the regency of Stilicho, ruled the western half of the empire while his brother Arcadius ruled the eastern half. His reign over the Western Roman Empire was notably precarious and chaotic. In 410, Rome was sacked for the first time in almost 800 years.
Honorius was born to Emperor Theodosius I and Empress Aelia Flaccilla on 9 September 384 in Constantinople. He was brother to Arcadius and Pulcheria. In 386, his mother died, and in 387, Theodosius married Galla who had taken a temporary refuge in Thessaloniki with her family, including her brother Valentinian II and mother Justina, away from usurper Magnus Maximus. Theodosius and Galla had a daughter, Galla Placidia, making Honorius her half-brother. Honorius, Arcadius, and Galla Placidia were the only children of Theodosius to survive into adulthood.
After holding the consulate at the age of two in 386, Honorius was declared augustus by his father Theodosius I, and thus co-ruler, on 23 January 393, after the death of Valentinian II and the usurpation of Eugenius. When Theodosius died, in January 395, Honorius and Arcadius divided the Empire, so that Honorius became Western Roman emperor at the age of ten.
During the early part of his reign, Honorius depended on the military leadership of the general Stilicho, who had been appointed by Theodosius and was of mixed Vandal and Roman ancestry. To strengthen his bonds with the young emperor and to make his grandchild an imperial heir, Stilicho married his daughter Maria, to him. The epithalamion written for the occasion by Stilicho's court poet Claudian survives. Honorius was also influenced by the Popes of Rome. So it was that Pope Innocent I and Western bishops may have been successful in persuading Honorius to write to his brother, arguing for convening a synod in Thessalonica.