On quitting the East, Maurice devolved his command upon an officer who bore the very common name of Johannes, but was distinguished further by the epithet of Mustacon, on account of his abundant moustache. This seems to have been a bad appointment. Mustacon was unequal to the position. He gave the Persians battle at the conjunction of the Nymphius with the Tigris, but was defeated with considerable loss, partly through the misconduct of one of his captains. He then laid siege to Arbas, a strong fort on the Persian side of the Nymphius, while the main body of the Persians were attacking Aphumon in the neighboring district of Arzanene. The garrison of Arbas made signals of distress, which speedily brought the Persian army to their aid; a second battle was fought at Arbas, and Mustacon was again defeated, and forced to retire across the Nymphius into Roman territory. His incapacity was now rendered so clearly evident that Maurice recalled him, and gave the command of the army of the East to a new general, Philippicus, his brother-in-law. The first and second campaigns of Philippicus, in the years A.D. 584 and 585, were of the most commonplace character. He avoided any general engagement, and contended himself with plundering inroads into the Persian territory on either side of the Upper Tigris, occasionally suffering considerably from want of water and provisions. The Persians on their part undertook no operations of importance until late in A.D. 585, when Philippicus had fallen sick. They then made attempts upon Monocartum and Martyropolis, which were unsuccessful, resulting only in the burning of a church and a monastery near the latter town. Neither side seemed capable of making any serious impression upon the other; and early the next year negotiations were resumed, which, however, resulted in nothing.