I forgot who it was, but I always found it so curious that it was recorded that Hephaistion was “wounded in the arm” during one of the battles. I know only the important things tended to be recorded, and of course, war and injury go hand-in-hand. I’m guessing that was pointed out because it was a really, really bad injury. Right? Not sure how that mention would’ve been relevant otherwise.
Hephaistion's Injury at Gaugamela
Arrian recorded Hephaistion’s injury.
In general, Arrian records a lot of military details that the other sources ignore or lack an interest in. Even so, with rare exceptions, his focus remains the army elite. And yes, Hephaistion is certainly among the elite, both owing to his importance to Alexander, but also, here, his role in the battle.
Diodoros tells us he fought first among the somatophylakes, or bodyguard. This has sometimes been misunderstood due to Diodoros’s tendency to mix-and-match terms. Diodoros doesn’t mean the 7-man unit of Somatophylakes, who didn’t fight together anyway. Their role as bodyguards was OFF the field. And I don’t think Hephaistion was a member of that unit yet anyway.
So what does he mean? The agema, or Royal squadron, of the Hypaspists. There were “regular” Hypaspists, and “royal” Hypaspists. Under Philip, this unit (then called Pezhetairoi) was the personal guard of the king in combat. When the unit itself came to be is a more involved discussion, but Philip made a significant change: he picked men for their size and fighting skill, not their high birth. Yet that was for the “regular” Hypaspists only, and it became one of the first pathways to advancement on skill alone in the Macedonian army. The royal unit, however, was another matter. Both Philip and Alexander made their military changes gradually.
Even under Philip, the Hypaspists were a stepping stone to higher commands for the sons of Hetairoi (Macedonian aristocrats). The whole unit was under the command of Nikanor, son of Parmenion. It was second only to the Companion Cavalry in prestige (which was commanded by Nikanor’s elder brother Philotas).
Yet overall command was different from unit command. E.g., Philotas commanded the Companions as a whole, but Kleitos Melas (Black Kleitos) commanded the Companion agema (royal unit) of Companion Cavalry. The king might lead that unit in battle, but he didn’t have time for the day-to-day duties of unit command, so Kleitos was their commander.
Similarly, by Gaugamela, Hephaistion had been advanced to command the Hypaspist agema. This may be why, later, Alexander advanced both him and Kleitos to joint command of the Companion Cavalry, after Philotas’s arrest and execution. Each had commanded the two most prestigious individual units in the army.
If Heckel is right (and I think he is), the Hypaspist agema at Gaugamela served as hammippoi, an elite form of hoplite who, literally, ran with the cavalry. (Keep in mind the horses would be mostly trotting or cantering, not galloping for long.) The job of the hammippoi was to help protect the horses and any cavalryman who was unhorsed, as the cavalry were much more lightly armed. But it’s a demanding job, to be sure.
At Gaugamela, Arrian tells us specifically of an encounter as Alexander returned with his Companion agema, after breaking off pursuit of Darius. They accidentally collided with some fleeing Persians and Indians (et al.), and it became the hardest fighting in the entire battle, as the fleeing men were desperate. I suspect this is where Hephaistion was wounded, as we’re told something like 60 Companions died in that engagement alone. It was brutal.
All that may help contextualize why Arrian names Hephaistion’s wounding. along with a couple others. He was the commander of a very important unit in the army.