In 392 Valentinian was secretly put to death at Vienne (in Gaul), and Arbogast, naming as his successor Eugenius, a rhetorician, descended into Italy to meet the expedition which Theodosius was heading against him.
About this time he was hampered by the persistent opposition of the vicechancellor Mikhail Vorontsov, formerly his friend, now his jealous rival, who was secretly supported by Frederick the Great.
What was more, Prussia, finding that Napoleon had secretly offered to the British Hanover (that gilded hook by which he caught her early in the year), now resolved to avenge this, the last of several insults.
Nevertheless Napoleon ordered the preliminary agreement to be considered as a definitive treaty, and on the 2nd of April gave instructions that one of the refractory cardinals should be carried off secretly by night from Fontainebleau, while the pontiff was to be guarded more closely than before.
After several victories he was at last completely defeated (306) and fled secretly to Sicily.