The Cultural History of Augustan Rome

Abstract

Perhaps the most striking connection to have been discovered in recent decades between an ancient text and an Augustan monument in the city of Rome is the solar meridian in the Campus Martius. 1 The text in question is Pliny's Natural History (36.72-3), which records that Augustus created a scientific instrument integrated with an obelisk he had erected in the Campus Martius. Pliny describes that instrument, whose design he attributed to a mathematician called Novius Facundus, in some detail. It consisted of a gilded ball on top of the obelisk and bronze markers embedded in a pavement, which was as long as the noontime shadow cast by the ball on the shortest day of the year. The markers permitted the position of the shadow of the ball to be measured every day at noon as the shadow of the obelisk became shorter with the lengthening days and then as it grew longer again with the shortening days. Pliny's account was long ago recognized as describing a solar meridian, which is to say a line running precisely north from the obelisk, which measured the progress of the noontime shadow every day through the sidereal year. 2 In 1980 the text of Pliny was confirmed by a remarkable discovery. The German Archeological Institute (DAI), at the instigation of its president, Edmund Buchner, conducted excavations directly to the north of the original location of the obelisk. There, beneath a building on Via di Campo Marzio, the excavators discovered part of a pavement with