Immediately after their senate confirmation, the emperors proceeded to the Castra Praetoria, the camp of the Praetorian Guard. Lucius addressed the assembled troops, which then acclaimed the pair as "imperatores". Then, like every new emperor since Claudius, Lucius promised the troops a special donative. This donative, however, was twice the size of those past: 20,000 sesterces (5,000 denarii) per capita, with more to officers. In return for this bounty, equivalent to several years' pay, the troops swore an oath to protect the emperors. The ceremony was perhaps not entirely necessary, given that Marcus's accession had been peaceful and unopposed, but it was good insurance against later military troubles. Upon his accession he also devalued the Roman currency. He decreased the silver purity of the denarius from 83.5% to 79% – the silver weight dropping from to .