The Alexandrina was built in 226 A.D. by Alexander Severus to supply his baths in the campus Martius. The springs which fed this aqueduct, and which partially supply the modern acqua Felice, are situated east of monte Falcone on the via Praenestina, between Gabii and lake Regillus, and about 20 kilometres from Rome. The total length of the channel was 22 kilometres. In 1585 Sixtus V built the acqua Felice in the same region and along nearly the same line. There are many remains of the original Alexandrina up to a point 3 kilometres from the city, but from there its course cannot be traced accurately. It is probable, however, that a piscina, the ruins of which have been found in what was formerly the vigna Conti, between the porta Maggiore and S. Croce in Gerusalemme, belonged to this aqueduct. According to measurements l taken in the seventeenth century, more than a third (9.7 kilometres) of its channel was above ground. Its ruins are to be seen in the valley of the acqua Bollicante on the via Praenestina.
buildings of Alexander Severus
The building projects of Alexander Severus as described within the The Scriptores Historiae Augustae.
...the Porticus Alexexandri Severi is in a totally incorrect position at the end of the Equiria, however, Piranesi may be making a suggestive link between Alexander Severus and the military. The small aedicule Isidis on the Equiria across from the Porticus may also be a reference to Alexander's devotion to his mother--Isis is the premiere mother goddess.
...the baths, aqueduct and his grove all comply correctly within the Ichnographia.
...the Domus (Palace of) Alexandri Severi is mentioned in the Historiae text, but it is not described, and my theory is that Piranesi placed Alexander's (house) Palace along the Triumphal Way (in the reverse mode) because he favored Christianity and the Golden Rule. The Domus Alexandri Severi is also exactly like the description of Elagabalus' Palace near the Porta Maggiore. Could Piranesi be weaving some complicated message which refers to both the reigns of Elagabalus and Alexander (which did follow each other, and they were cousins), where Alexander successfully undid the corruption of Elagabalus and began to turn Rome toward a more Christian and morally sound city and empire?
...not yet sure, but I think Alexander Severus' name is attached to more buildings within the Ichnographia second only to Nero.
a Roman emperor, A.D. 222-235.
Alexander Severus is one of four Roman emperors from the third century associated with buildings and specific sites delineated within the Ichnographia Campus Martius. Caracalla, Geta, and Gordian III are the other third century emperors named in the Ichnographia, however the number of building attributions apropos Alexander Severus substantially outnumber those of these emperors, and, Alexander Severus is indeed second only to the emperor Nero in the number of structures and places within the Ichnographia that bear his name. It is historically true that ample building activity in the Campus Martius occurred during Alexander Severus' reign, and, with one notable exception, Piranesi positions the Alexander Servian constructions with acceptable correctness within his large plan -- the placement of the Thermae Alexandri Severi, Nemus Alexandri Severi, and the Aqua Alexandrina (the Baths, Grove, and Aqueduct of Alexander Severus respectively) in the area west of the Thermae Agrippa and nearby the Thermae Neronianae coincides with corresponding verifiable archeological locations. Piranesi's positioning of the Porticus Alexandri Severi, on the other hand, at the end of the Equiria, far to the north of the Campus Martius, deviates grossly from its traditional location near the Saepta Julia.
The only questionable building that Piranesi attributes to Alexander Severus within the Ichnographia, which may or may not have actually been within the Campus Martius, is the Domus Alexandri Severi.