Slavery is a cultural and economic system in which people are treated as property. Slaves are sold, traded, and forced to work for their "owners." It is unknown how long slavery has been practiced on Nirn, but the oldest mention dates back to the time of the Ayleids. Also known as the "Heartland High Elves," the Ayleids enslaved the Nedic humans. Among them was Saint Alessia, liberator of the slaves. After the Ayleids fled Cyrodiil and integrated with the Bosmer cultures in Valenwood, slavery did not re-emerge until much later, where beastfolk such as Argonians and Khajiit were enslaved by elves and men alike. In the Fourth Era, slavery has become a rare practice, having been outlawed in Morrowind.
The Ayleids kept human slaves, when their empire ruled the Cyrodilic province. Generally, the Ayleids worshipped the Altmeri divines, but also dealt frequently with Daedric Princes for assistance in keeping their slaves in line. The Nords of Skyrim worshiped a distinct group of divines, who were much more sympathetic to humanity than merfolk. Alessia began to pray to these divines for assistance in freeing her people, in particular Kynareth, whom the Nords called Kyne.
Kynareth sent her son, the Nordic demi-god hero Morihaus, to advise and aid Alessia. During this period, Morihaus is usually identified as Alessia's lover, though the Song of Pelinal claims he was embarrassed at his appearance because of her. He helped her to rally the other slaves to her cause. From that moment she was known as the Slave-queen. Kynareth also sent Alessia visions that would aid her fight against her masters. The third of these visions was of another legendary figure of the First Era, the infamous Pelinal Whitestrake, who was sent to Alessia to become the leader of her army. Pelinal was a demi-god like Morihaus, possibly the son of Lorkhan.
Dunmer have traditionally permitted enslavement of Imperials, Nords, Orcs, Khajiit, and most importantly Argonians. They do not recognize the mistreatment of slaves of these races as a serious crime, other than as a crime against property. By the terms of the Treaty of the Armistice, Morrowind may define its own laws and customs, and slavery remains legal. For ages the Dunmer, particularly House Dres, have raided Black Marsh for slaves; though the Empire has made this illegal, the practice persists, and Dunmer and Argonians have a long-standing and bitter hatred for one another. Slavery is uncommon in Redoran and Hlaalu districts, but common in Telvanni Districts. The slavery finally ended in conflict and the Arnesian War started, although the war didn't help freeing the slaves.
Slavery is protected by law in Morrowind. Slavery is illegal throughout the Empire, and considered barbaric. Slavery had disappeared in the Summerset Isles and Valenwood long before their incorporation into the Empire. Most Imperial citizens assume the practice will die out as Morrowind adopts Imperial ways, and the subject excites little passion except among Argonian and Khajiit abolitionists, outraged that the Empire does little to suppress persistent illegal cross border slave raiding in southern Morrowind. House Dres is actively against Imperial activity in Morrowind, largely due to the Imperial policies against slavery. 
It is said that in 2E 582, slavery is still legal within the borders of Morrowind because of its belief and economic structure. However, due to the Ebonheart Pact, all Argonian slaves must be liberated. The main slave race was then Khajiit.
The Ayleids were well known for their cruel tradition of keeping many slaves. They were said to herd men from all across Nibenay, such as the Kothringi, Nedes, al-gemha, men-of-'kreath, men-of-ket Keptu, men-of-ge, and al-hared. The Alessian Slave Rebellion put an end to this, and city-states that allied with Alessia, like Nenalata, were also forced to transition to a slaveless economy. While not a common practice among Imperials, Tiber Septim sold captive Bretons into slavery after defeating them in the Battle of Sancre Tor.
The Altmer have often kept Goblins as slaves, though this practice is usually on the main Isle of Summerset. After being annexed into the Third Empire, slavery was discontinued. It is unknown if the Third Aldmeri Dominion brought back the practice of slavery.
Argonians have not traditionally kept slaves, as they despise the enslavement of their kind by the Dunmer. However, under the effects of the Mad Hist, the Xit-Xaht tribe enslaved many of their own species to rebuild the Ruins of Mazzatun. Argonian mothers would sometimes sell their own children into slavery. In Thorn, a city in Black Marsh that heavily influenced by Morrowind due to being on the province's border, the Archein clan kept many slaves in and around the city. They were generally despised by their own kind, whom considered them traitors.
Following the Nordic-Falmer War, most Snow Elves sought refuge with the Dwemer, but in exchange for protection they had to eat toxic fungus that would blind and eventually degenerate them, while being servants to the Dwemer. Those who agreed became the savage Falmer, while most whom declined the deal perished.
An Argonian slave known as Walks-Softly was brought from Black Marsh to Hew's Bane and kept as a slave, before running away and being replaced by Pimsy. Due to the region not being under the control of Forebear High King Fahara'jad, it is unknown what the rest of Hammerfell's views on slavery is.
Despite slavery's acceptance in Morrowind, there are still factions who assist in the freeing of slaves, the most famous being Twin Lamps. While the group existed long before Imperial involvement, they are assisted by outside sources, includes some within the Thieves Guild when it comes to freeing and smuggling slaves out of Morrowind.
- The Elder Scrolls Adventures: Redguard (Mentioned only)
- The Elder Scrolls III: Morrowind
- The Elder Scrolls IV: Oblivion (Mentioned only)
- The Elder Scrolls V: Skyrim
- The Elder Scrolls Online
- ↑ The Song of Pelinal
- ↑ Trials of St. Alessia
- ↑ Provinces of Tamriel
- ↑ Great Houses of Morrowind
- ↑ Overheard rumors inOblivion
- ↑ The Adabal-a
- ↑ A Life of Strife and Struggle
- ↑ Battle of Sancre Tor (Book)
- ↑ Dialogue of Byz
- ↑ Events of Shadows of the Hist
- ↑ 11.0 11.1 The Argonian Account, Book IV
- ↑ The Argonian Account, Book III
- ↑ From Argonian to Saxhleel
- ↑ Dialogue of Knight-Paladin Gelebor
- ↑ Events of Skyrim
- ↑ Events of Thieves Guild