After the end of the Severan Dynasty in 235, the Empire entered into a 50-year period known as the Crisis of the Third Century during which there were numerous putsches by generals, who sought to secure the region of the empire they were entrusted with due to the weakness of central authority in Rome. There was the so-called Gallic Empire from 260 to 274 and the revolts of Zenobia and her father from the mid-260s which sought to fend off Persian incursions. Some regions – Britain, Spain, and North Africa – were hardly affected. Instability caused economic deterioration, and there was a rapid rise in inflation as the government debased the currency in order to meet expenses. The Germanic tribes along the Rhine and north of the Balkans made serious, uncoordinated incursions from the 250s-280s that were more like giant raiding parties rather than attempts to settle. The Persian Empire invaded from the east several times during the 230s to 260s but were eventually defeated.