beyond AD 450, due to excessive grant. In many cases, the title was granted ex officio, but it could also be purely honorary. In the military sphere, the title of comes primi ordinis was granted to a group of senior tribuni. These included (1) the commander of the protectores domestici, who by 350 was known as the comes domesticorum; (2) some tribuni of scholae: after c. 400, scholae commanders were routinely granted the title on appointment; (3) the commanders of a brigade of two twinned comitatus regiments were apparently styled comites. (Such twinned regiments would always operate and transfer together e.g. the legions Ioviani and Herculiani); (4) finally, some tribunes without a regimental command (tribuni vacantes), who served as staff-officers to the emperor or to a magister militum, might be granted the title. These officers were not equal in military rank with a comes rei militaris, who was a corps commander (usually of a smaller diocesan comitatus), rather than the commander of only one or two regiments (or none). Corps commanders (duces, comites rei militaris, magistri militum) The commanders of army corps, i.e. army groups composed of several regiments, were known as (in ascending order of rank): duces limitis, comites rei militaris, and magistri militum. These officers corresponded in rank to generals and field marshals in modern armies. A Dux (or, rarely, comes) limitis (lit. "Border Leader"), was in command of the troops (limitanei), and fluvial flotillas, deployed in a border province. Until the time of Constantine I, the dux reported to the vicarius of the diocese in which their forces were deployed. After c. 360, the duces generally reported to the commander of the comitatus deployed in their diocese (whether a magister militum or comes). However, they were entitled to correspond directly with the emperor, as various imperial rescripts show. A few border commanders were, exceptionally, styled comes e.g. the comes litoris Saxonici ("Count of the Saxon Shore") in Britain. A Comes rei militaris (lit. "Companion for Military Affairs") was generally in command of a smaller diocesan comitatus (typically ca. 10,000 strong). By the time of the Notitia, comites were mainly found in the West, because of the fragmentation of the western comitatus into a number of smaller groups. In the East, there were 2 comites rei militaris, in command of Egypt and Isauria. Exceptionally, these men were in command of limitanei regiments only. Their title may be due