Slavery in
Middle-earth was probably ubiquitous, as it was in our real world and remains to this day in some
places in our world, though perhaps other words and terms with less impact are used to describe it.
Morgoth was the first slaver in
Tolkien’s mythos, taking
Elves from
Cuiviénen whom he corrupted into the original
Orcs. During the
First Age, he enslaved
Sindar, Exiled
Noldor, Dark Elves (i.e., Avari), and
Men, whom he worked to death in his mines, forges, and smithies, besides whatever other nefarious uses to which he put them.
Sauron also took and enslaved these people during the First Age: when
Lúthien spoke the words that bound together the stones of the Wizard’s Tower on Tol-in-Gaurhoth, they came forth blinking in the light of morning. Men also kept slaves: the folk of the
House of Hador living in Hithlum were enslaved after their defeat in the
Nirnaeth Arnoediad by the
Easterlings who followed Ulfang the Treacherous, so I think we may safely assume that Men in the rest of Middle-earth were also in the habit of keeping slaves.
The
Second Age seems to have begun with considerably less slavery, particularly in the coastal
regions and in Eregion. In the
White Mountains of what later became
Gondor, worshippers of Sauron took
Númenórean settlers as slaves, according to the tale “Tal-Elmar” in
Peoples of Middle-earth, though the Númenórean captain told Tal-Elmar the
Númenóreans did not keep slaves. Besides whatever Men were doing beyond the knowledge of the Eldar, Orcs continued to take and keep slaves for the same purposes as Morgoth had, for mining, forging, and smithying, as well, likely, for growing
food. As the Shadow fell upon
Númenor following the War of the Elves and Sauron (
likely due to the influence of the three Númenóreans who held Rings of Power) and their rebellion against the
Valar began to take shape, Númenóreans among the King’s Men might have begun enslaving some of the inhabitants of Middle-earth. I think the indication is that slavery became more widespread as the Second Age drew toward a close, until the unfortunate natives of Middle-earth in many cases probably found themselves facing the dire choice of ruinous, utter slavery under the followers of Sauron and the increasing tribute demands of the Númenóreans, tribute that might or
might not include slavery, but would likely include
corvée labor (intermittent unpaid forced labor). I don’t think that slavery by Númenóreans during the Second Age is ever made explicit in Tolkien’s work, though certainly tribute is, and I imagine forced labor – corvée labor,
serfdom (not slavery, but where a peasant is unable to leave the land he works), perhaps eventually including slavery – was practiced in those regions dominated by the King’s Men, which would be most Númenórean territory in Middle-earth.
The Third Age would seem (to me) to continue conditions at the end of the Second Age. Orcs continued to seize folk as slaves. The
Haradrim might be expected to practice it. Various
Easterling invaders took slaves from the folk of
Rhovanion and from northern Gondor (Calenardhon in particular:
Rohan did not yet exist), and after the Kin-Strife and the desertion by the navy of Gondor to
Umbar, the
Corsairs of Umbar took slaves from the coastlands of Gondor. Certainly upon his return to
Mordor, Sauron maintained a vast empire of slaves which he replenished with captives sent from
Harad and Rhûn: the lands around the Sea of Núrnen were devoted to growing food to feed Sauron’s
armies.
There is no mention of Elves keeping slaves, and no mention either of the
Edain or
the Faithful Númenóreans or their Exiled descendants keeping slaves. I am quite certain there must have been poor people among them, often heavily indebted in a world (at least in the late Third Age) with little currency in circulation, but there is no mention of slavery in
Eriador or
Wilderland besides the Orcs,
except in
Isengard, where
Saruman had enslaved people to tend
fields to feed his armies. Nor is there ever any mention of
Dwarves or
Hobbits keeping slaves.
As an aside, I think the
Entwives were probably taken and enslaved by Sauron. Tolkien suggests this might have been the case (see
Letter 144). The appearance of the
Olog-hai, their clever intelligence, their speed, and their resistance to the sun suggest to me that they were likely some developed through some corruption of
Ents:
Treebeard himself hints at this: “
Trolls are … counterfeits made by [Morgoth] in mockery of Ents, as Orcs were of Elves.” (“Treebeard”,
Two Towers) Just as the
Uruk-hai of the late Third Age were stronger and fiercer that normal Orcs and could tolerate the sun, so also the Olog-hai were stronger, fiercer, and smarter than Trolls and could tolerate the Sun. Treebeard suspected the Uruk-hai were Orcs mixed with Men; I suspect the Olog-hai were Trolls mixed with Entwives.
