Das Wertverhältnis des alexandrinischen Billon-Tetradrachmons zur Reichswährung unter Augustus und Tiberius

Abstract

The papyrus roll ChLA XLIII 1241 provides previously unnoticed information on the exchange rate between the empire-wide currency, i.e. the aureus, and the Egyptian drachma. The exchange rate of the denarius and the late Ptolemaic billon tetradrachm under Augustus was 1:1,25, which corresponds almost exactly to the ratio of the silver content of both denominations. The rate of 1:1, which is securely attested from the end of the first century AD, was accordingly established under Tiberius. This is supported by the fact that the revaluation of the Alexandrian tetradrachm – its value now, as we see, being reduced by a fifth – was accompanied by a reduction of the silver content of the denomination also by a fifth. Papyrological evidence and numismatic metal analyses thus form a coherent picture.