The Senatus-Prætoriani Interregis was a strict and formal (though at the same time fragile) agreement lasting from 943(190) to 948(195) between the Senate and the Praetorian guard following Cæsar Commodus' execution. The Interregis was declared upon the execution of Commodus and most of his supporters in the Senate and military, but it was already known that various elements would take the opportunity to seize power. These elements came mostly from the east where the highest concentration of imperial legions were stationed. Most were dealt with quietly, however three greatly marked the Interregis.