Under the Byzantine Emperor Justinian I, several parts of the colonnade were restored. The street was narrowed to 12 m by adding a walkway on either side. Several stretches of the street had their Roman pavement replaced with a new pavement made of squared blocks of limestone. The new pavement also covered a completely overhauled drainage system. Justinian's changes included erecting a monumental "tetrastylon" made up of four 9 m high columns with a metre-high capitals. The city, was however, later sacked by the Sasanians under Adarmahan.