This study explores the origins and development of two dress types, the loros (a late form of the toga) and the sakkos (initially a form of everyday robe), in particular investigating the sequence of their adoption by the Imperial court and by ecclesiastical officials. It draws on a wide range of sources, among them, archaeological, liturgical, literary, numismatic and art historical. Among the influences on the form of these vestments, attention is focused on Persian costume, as well as the western Late Roman influences which are more often assumed.