In 69 BC Lucullus invaded Armenia. He began a siege of the new Armenian imperial capital of Tigranocerta in the Arzenene district. Tigranes returned from mopping up a Seleucid rebellion in Syria with an experienced army which Lucullus nonetheless annihilated at the Battle of Tigranocerta. This battle was fought on the same (pre-Julian) calendar date as the Roman disaster at Arausio 36 years earlier, the day before the Nones of October according to the reckoning of the time (or October 6), which is Julian October 16, 69 BC. Tigranes retired to the northern regions of his kingdom to gather another army and defend his hereditary capital of Artaxata, while Lucullus moved off south-eastwards to the kingdom of the Corduene on the frontiers of the Armenian and Parthian empires. During the winter of 69–68 BC both sides opened negotiations with the Parthian king, Arsaces XVI, who was presently defending himself against a major onslaught from his rival Phraates III coming from Bactria and the far east.