L’entrée septentrionale du palais impérial de Thessalonique : l’arc de triomphe et le vestibulum d’après les fouilles d’Ejnar Dyggve en 1939

In the months from early March through June 1939, the Danish archaeologist Ejnar Dyggve carried out extensive excavations in Thessaloniki. Work centered on the Rotonda, on the area between the Rotunda, the Arch of Galerius and the Odos Egnatia, and on the areas south of the Egnatia. Due to World War II, the results were only partially published in preliminary articles and reports. The present paper first provides a short discussion of seven trial digs carried out to the south of the Egnatia. The main focus is on the large building (42.70 x ca. 17.65 m), which was partially unearthed immediately to the south of the existing Arch (beneath the actual Odos Egnatia). Structurally, the building was shown to form a component unit of the now-destroyed southern section of the Arch. Decorated with splendid floor mosaics and communicating with the (ca. 2.4 m) lower, southern terrain by means of a monumental marble stairway (of approximately 18 m width), the building was interpreted as a vestibulum, joining the residential quarters of the palace and the Rotunda, which are separated by the Egnatia.