In 163, the Parthians intervened in Osroene, a Roman client in upper Mesopotamia centred on Edessa, and installed their own king on its throne. In response, Roman forces were moved downstream, to cross the Euphrates at a more southerly point. Before the end of 163, however, Roman forces had moved north to occupy Dausara and Nicephorium on the northern, Parthian bank. Soon after the conquest of the north bank of the Euphrates, other Roman forces moved on Osroene from Armenia, taking Anthemusia, a town southwest of Edessa.