After the sack of the city by the Vandal king Geiseric in 455, he fled to Constantinople, where in 464 he was made consul, and about the same time married Placidia, daughter of Valentinian III and Eudoxia. This afforded Geiseric, whose son Huneric had married Eudocia, the elder sister of Placidia, the opportunity of claiming the empire of the West for Olybrius. In fact, Geiseric had attempted in 461 and again in 465 to get Olybrius made emperor.
In 472 Olybrius was sent to Italy by the emperor Leo I to assist the emperor Anthemius against his son-in-law Ricimer, but, having entered into negotiations with the latter, was himself proclaimed emperor against his will, and on the murder of his rival ascended the throne unopposed. Because of his marriage to Placidia, Olybrius can be considered the last member of the House of Theodosius. His reign was otherwise as uneventful as it was brief.
Using text from a 1911 encyclopedia
Anthemius (467 - 472)
Glycerius (473 - 474)