Ok, so first, the commercial. Chronicles II: The Black Dog Caliphate is now available for Barons of Braunstein. This one's set in medieval Cairo, more specifically, in the desert following the imaginary Small Nile. If this resonates, check it out. End of commercial; but it raises important questions about historical magic. The supernatural defies all boundries, meaning there's no way to get it wrong beyond ill-concieved mechanics...
But since Braunstein has an optional fantasy component; and especially since this has to channel historical conceptions, it's worth noting that modern gaming magic bears little resemblance to how it was imagined, especially under medieval Chistendom. But it's also clear that OD&D, cheerfully unencumbered by decades of convention, hewed closer to historical and folkloric traditions, which often included minions...
And spirits. Historical magicians called and commanded spirits. And they had minions, which overlapped these in places. Barons of Braunstein goes this route; but while OD&D wisely avoided having its magic users summon evil spirits, it nonetheless channeled its mythological inspirations - and the media equally inspired by it - leaning into minions as a substitute for demons. This is seen in earlier mainstream fantasy films predating the hobby...
The Seventh Voyage of Sindbad had Sokurah. And Sokurah had a genie. And a dragon. And skeletal servitors. Jack the Giant Killer had Pendragon, who in turn had a cadre of giants, hobgoblins, and witches at his command. The latter wasn't Harryhausen. Jim Danforth lent his stop motion talents, noting that both wizards were played by Torin Thatcher, with their assembled servitors figuring prominently as the source of their powers.
So what did OD&D offer? The Charm spell, which, unlike later editions, affected a greater variety of targets, including gnolls and nixies, without regard to level if its (very broad) criteria was otherwise satisfied - with but a single saving throw ever. Even novice magicians might amass a cadre of powerful slaves, with Charm Monster (starting at 7th level) bedazzling any adversary, with multiple 1-3rd level animals, also with but a single saving throw...
This speaks to how powerful OD&D's magic was, but also to the numerous influences behind its magic system. Arneson famously watched monster movies, and Gygax surely enjoyed Harryhausen, where Sokurah called forth minions. Vance likewise inspired OD&D; but if you want traditional (historical and folkloric) magic, servitors are a must. Of course, the game became squeamish later on; but the early rules had more powerful charms.
So what's the point of this? After writing a historical adventure with magical options, the importance of servitors is obvious. The Tempest's Prospero summoned spirits, and minions reflect a historical conception of magic. No self-respecting wizard is without their tower of mesmerized monsters to challenge intruders; and in OD&D, that fantastic medieval wargame, charms are not only a nice alternative, but perhaps the mightiest of all high sorceries...