Samuel Ball Platner, Thomas Ashby, A Topographical Dictionary of Ancient Rome

CASTRA EQUITUM SINGULARIUM

the barracks of the equites singulares, a select corps of cavalry organised about the end of the first century as a bodyguard for the emperor. Some remains of these barracks were found in 1885 in the Via Tasso, just north-west of the Scala Santa, consisting principally of the wall of a large rectangular court, in which were niches and in front of the niches inscribed pedestals (BC 1885, 137; Ann. d. Inst. 1885, 235 ; PT 131). These inscriptions and others found near by (CIL vi. 31138-31187) mention castra priora and castra nova or nova Severiana, and one MS. of the Notitia reads castra eq. sing. 11. There were, therefore, two barracks, the later apparently erected by Severus, but they were probably adjacent structures, or even parts of the same building (HJ 246; DE ii. 2148). Other fragments of walls that probably belong to the castra have been found in front of the Lateran (BC 1913, 72-74).