Oh dear, I guess I am not expressing myself very well – and you have rather jumped the gun a little, for I intended to post more, as I said in my last post.....I am trying not to post in “chunks” that are too large to digest, or respond to....pretty well all scholars agree that the 'Agema' was the leading ( or senior) sub-unit of the 'Hypaspist's, whose role was that of foot guard on the battlefield and elsewhere. They are a ‘regular army unit’, much like the Guards Division in the modern British Army. But the point of my digression is that ‘somatophylakes’ and ‘agema’ are NOT synonyms. This is pure assumption, unsupported by any evidence.I am afraid this does not wash at all; Arrian frequently writes ‘the agema and the hypaspists’ (I 1 xi , I 8 iii, II 8 iii, VII 7 i) or even ‘the agema and the other hypaspists’ (III 11 ix, V 13 iv) given that all the examples of ‘somatophylakes and hypaspists’ occur in analogous combat situations and are therefore analogous constructions where ‘somatophylakes’ is used as a synonym for ‘agema’; there is no reason to posit a separate guard formation. Aristoboulos and Ptolemy do use different terms for the same thing, taxis/phalanx for the individual battalions for instance, prodromoi/sarssophoroi for another.
Remember Sir Francis Bacon ? Here is a perfect instance, to the point where translators alter the text to conform to the assumption! The confusion arises because on the battlefield the Hypaspists, and the Agema in particular are ‘foot guards’ whose role, should the occasion arise, is to protect the King but, as I tried to point out, there is a difference between the ‘Foot Guards’ and a ‘Bodyguard’, whose main role is to closely protect the King in a personal sense off the battlefield, 24/7, even if their functions overlap to a degree. Is there evidence that they are separate units ? Yes !
The ‘somatophylakes’ are a mounted body at Pelion (Arrian I.6), who ride with the Companion cavalry.(hence not infantry Hypaspists). On the other three occasions that we hear of them in action in Arrian ( III.17, IV.3 and IV.30, taking part in a raid, sneakily capturing the way into a city, and scaling Aornus respectively) they are accompanied by Hyspaspists, but not part of them; “Somatophylakes and the Hypaspists...”etc - and often others too, and all 'special task forces', not in pitched battle. Nor am I positing a ‘new’ guard unit, as we shall see. There is another piece of evidence for the ‘somatophylakes’ not being part of the Hypaspists, namely Diodorus XVII.61 at Gaugemala where Hephaistion “..commanded the somatophylakes/bodyguards” and was wounded. These bodyguards are not the Hypaspists, for at this time they were commanded by Nicanor, son of Parmenion, and must be a separate unit .(Arrian III.21.8 )
As to multiple names for units, yes, those existed then as now – often a unit will have an ‘official’ name and a nickname – a modern example is the U.S. Marines a.k.a leathernecks, and the Prodromoi/scouts were also nicknamed sarissaphoroi/lancers. But taxis/phalanx is not an example. ‘Taxis’ in a Macedonian context is best translated ‘brigade’, about 2,000 strong, [Yes, I know, we have to resume that discussion at some point! ] made up of ‘battalions/syntagma’ or ‘speira’ 256 strong. ‘Phalanx’ is best literally translated as ‘roller’ and refers to the main infantry battle line, which could be one or many ‘taxeis’. But the ‘Somatophylakes’ are clearly not the ‘Agema’ – and we need look no further than the assassination of Philip described at Diodorus XVI.93-94, where the ‘S’ are 20 year olds, not full ‘armed guards’ etc. To be in the regular military, such as the Hypaspists, one had to be an adult i.e. over 21.
Again, I am perhaps not clear. I was not suggesting that the “S.” (getting tired of typing the word in fullWere there to be then they are clearly a full military unit with combat functions and not a police force, which undermines the distinction you wish to impose on the Diodoros passage (XVI 93-4). There, the words are used by Diodoros’ Greek source for variety and should not be taken in any technical sense. In fact the description does not just oscillate between ‘doryphoroi’ and somatophylakes’ but includes the ‘spear-bearing Guards’ – doryphoroi phylakes and ‘those friends around him’ - philous keleusantos .

When I have some more time, I shall check to see if Curtius' equivalent latin terms - 'armigeri' and 'corpores custodi' are also used consistently....
Fair point, that is a possibility – but one which ignores Philip’s attested purpose of NOT wishing to be attended by fully armed guards, but to keep these at a distance. Pausanias must have been within 5 metres or so, for if he ran at Philip from much further, someone would have shouted a warning to the King. That is why he is a ‘somatophylax’, not a ‘doryphoroi’. (Plutarch notwithstanding.)It is clear from the narrative that no one is around Philip when Pausanias dashes up to strike; and that is the point of a concealed drawn weapon, the ability to strike without drawing the blade gives the assassin a great advantage in surprise, maybe even more so if his sword is plainly sheathed by his side!
Agreed.As a picky point, Aelian calls the weapon a ‘xiphos’ but both ‘xiphos’ and ‘gladius’ are catch all words for swords, what we would simply call a ‘gladius’ would be a ‘gladius hispaniensis’ or Spanish sword to a technically minded Roman. Both represent a later and diverse tradition, Aelian explicitly states that the account differ, though it is the significance of the chariot warning that interests him; and Justin because he uses gladius rather than pugio (a dagger) for the weapon, by implication his source used ‘xiphos’ as in Aelian.
Agreed.Diodoros was only writing 100 years before Plutarch and their sources were probably both contemporary Greeks, Diodoros almost certainly used Theopompos’ ‘Philippic History’, Plutarch could have used any Greek source (the Macedonian, Marsyas seems ruled out by the general term ‘doryphoros’ rather than a specifically Macedonian term; ‘doryphoroi’ do not figure in Arrian’s narrative which follows Macedonian PT/Ar sources.)
Having brought in Diodorus, perhaps it might be as well to refer to his other references to ‘somatophylakes’. Apart from Philip’s assassination at XVI.93-94, and the reference to Hephaistion as their commander at XVII.61, there is a reference to Alexander ordering ‘S’ to grab an Indian who is mutilating a fighting dog at XVII.92. There are three other references to “S.” after Alexander’s death at XVIII.2; XVIII.87; and XIX.14, but these are all references to ‘the Seven’.
Essentially we are agreed about the Paides – that they were the sons of the leading nobles who entered service around puberty/age 15 ( other Macedonians began military training at this age). You believe they ‘graduated’ to manhood at 18 ( no real evidence for this) while to me the evidence (epigraphic and other) points to 21 being the age of becoming an adult male, and entering the Military. You believe they then went into a ‘new’ unit of young nobles at 18, and in seeking to identify such a unit, proposed 'hoi hetairoi amph 'auton' and it's many variations; while to me ( and Paralus) this expression does not sound like a unit title but rather a description of Alexander’s immediate entourage on any one particular occasion. We both agree that the 19-20 year-old young nobles (epheboi) attended and guarded the King both by day and by night (Curtius VIII.6.18).
My hypothesis is that in fact this group of 100 or so, whether technically still within the ‘paides’, as I believe, or without in a ‘new’ unit as you believe ( even though non-adult Greeks did not generally serve in the Military) were called the ‘Somatophylakes’. This hypothesis is consistent with all the known data that I am aware of.
Thus we have the term used in a titular sense for “the Seven”, those closest to Alexander, and also for the actual ‘bodyguards’, the young noblemen 19-20 years old whom I believe were a sub-group of the ‘paides.’(just as the 'Agema' were a sub-group within the 'Hypaspists')
It is generally agreed that the references to 'somatophylakes' in Arrian are not just to the "Seven", therefore there is another group called by this title.( e.g. IV.30 where A. takes 700 somatophylakes and Hypaspists)
At 21 they became ‘adults’, and were dispersed/graduated into the regular Army, probably mostly to 'Hetairoi' or 'Hypaspists', especially the ‘Ile Basilikoi’ or the ‘Agema’, but some perhaps to their ‘family and tribal’ units as Alexias suggested.....