In the Moldvay Basic Set they were called retainers, in AD&D they used the term henchmen, and nowadays they go by the moniker cohorts. In supers games they're usually called sidekicks. Whatever the label, I love PCs with their own trusty shield-man. As a DM I squeal with glee when PCs recruit junior adventurers to fight by their side. Two of my favorite characters from my old Bandit Kingdoms campaign were Sam and Tobit, the NPC henchthugs of Doctor (later Baron) Phostarius, Pat's chaotic bard/mage.
Until 3E made you buy your cohorts with feats a lot of DMs I knew weren't as hench-friendly as I. That anti-retainer bias combined with my tendency to DM rather than play resulted in me going over 20 years before I had a proper cohort for one of my own D&D characters. In Jon's World of Alidor game I've finally achieved henchitude. Here's a Heromachine rendering of Abu of the Thousand Scars, the xeph soulknife/rogue sidekick to my guy, Osric the Slayer.
His thousand scars are the result of henious mistreatment at the hands of the Dragon Worshipping Cannibal Halflings.
I'm so new at running a cohort that for the last two sessions I forget to give poor Abu his fair share of the XPs. He may have leveled and I don't even know it!