The long structure on the west side of the church was an ardica ( narthex or porch) of the church. Originally it was preceded by a courtyard, which was replaced by a quadrangle of the monastery in the 10c. Thee are two entrances from the ardica to the church. The current tourist entrance is on the south side of the church, however, and the exit towards the Mausoleum of Galla Placidia is on the northl.