The Churches of Galla Placidia Augusta
Among the Christian emperors and empresses Galla Placidia Augusta has a distinguished record as a great builder to the glory of God, and deservedly so, for if the casual American or European retains any recollection of the Empress, it is likely to be as a builder of churches.
In the imperial City [Rome] itself the name Galla Placidia is still most conspicuously to be seen in the Basilica of Saint Paul-outside-the-Walls. The first half of the pontificate of Pope Saint Leo the Great coincided with the last ten years of the life of Galla Placidia. During that period she apparently contributed heavily to the restoration of Saint Paul's, which had been severely damaged by a thunderbolt.
The Roman church now known as Santa Croce in Gerusalemme, but originally Santa Hierusalem (Jerusalem) was built not by Constantine the Great, as Christian tradition has it, but by one of his successors; a hall of the Sessorian Palace, former residence of the Empress Saint Helena, mother of Constantine, was utilized for the purpose. [The case that Eutropia, the mother-in-law of Constantine built Santa Hierusalem is already within the text of "Theatrics Times Two" and will presented in full with "Augustacopia".] The church was supposed to contain a fragment of the true cross which Saint Helena was reputed to have found in Jerusalem. Galla Placidia, acting also in the name of her son and daughter, consecrated mosaics here sometime before the year 438; an inscription now lost recorded the fact: "May the kings of the earth and all peoples, leaders, and all judges of earth praise the name of the Lord. Valentinian, Placidia, and Honoria, Augusti, have paid their vow to the Holy Church Hierusalem."
In accordance with her vow of 423 Placidia constructed in the imperial quarter [of Ravenna] a church in honor of saint John the Evangelist. We may assume under the circumstances that the building was erected not long after her accession to power in 425; in any case it must have been built and dedicated before 438. Unfortunately the building which honors the saint in Ravenna today is a twentieth-century learned reconstruction of the Empress's church, which carefully incorporates the rather insignificant surviving fragments of her original structure.
The principle church of the imperial quarter of Ravenna was that of the Holy Cross (Santa Croce), which Galla Placidia also either constructed or embellished, to serve in effect as a chapel for the palace. It was filled with works of art and value, mosaics and marbles, honoring "Christ, the Father's Word, the Concord of the whole world." This church has also long since vanished, and the building that stands on the site and is known by its name has little other connection with the ancient edifice.
The Empress also contributed precious gifts to the Cathedral of Ravenna, the Basilica Ursiana; this building, too, no longer exists and has been replaced by a nondescript modern structure. It is also possible that she contributed to Saint John the Baptist at Ravenna, and if our ninth-century informant can be trusted and there is a kernel of truth in a miraculous story he tells about Singledia, the niece of the Empress (otherwise unknown, but possibly a relative of Constantius or Athaulf); she eagerly seconded Singledia's building of a shrine to Saint Zacharias, the father of the Baptist, and presented it with a chalice. At Ariminum (Rimini), Ravenna's neighbor to the south, she erected a church for Saint Stephen, also now vanished.
Stewart Irvin Oost, Galla Placidia Augusta (Chicago: The University of Chicago Press, 1968), pp.269-278.