Artifacts are special items with unique names that can be obtained by various means: using the Stealing skill to pilfer them from disparate locales, through specific monster drop systems, during events associated with game-wide fiction, or by crafting them using rare ingredients.

Named items obtained from the old Seer Quests were not considered Artifacts when they were being given to players, largely because the term had not yet been invented. The term and concept have not been "retro-fitted" to apply to these older items.

The items considered to be the first Artifacts were introduced in the Age of Shadows expansion, in the dungeon Doom, using two methods.

First, various items spawned throughout the dungeon that could only be picked up by using the Stealing skill. This was a move by the development team to vindicate the concept of collecting Rares and as a throwback to the way that Rares had originally been created. That is, as items unobtainable to players, that had been used to decorate the environment, but which had been accidentally left unlocked and could be picked up and carried away. The newly stealable items in Doom spawned with the new property Artifact Rarity, which denoted the frequency with which they spawned.

The second method by which original Artifacts entered the game was as a group of items that could be obtained in the Doom Gauntlet, as rare drops that went directly into a character's backpack. These too, possessed the Artifact Rarity property, but since these Artifacts spawned in relation to monster slaying, the Artifact Rarity did not always directly correlate to spawn frequency. Many of these type of Artifacts have entered the game, making the Artifact Rarity misleading.

When the Paragon system was introduced in 2004, people began calling the named items that dropped "Minor Artifacts" due to the system's similarity to the Gauntlet and the unique names that the items possessed, even though these items did not possess the Artifact Rarity property. This custom was repeated for the Treasures of Tokuno events and later for craftable Artifact quality items introduced with Mondain's Legacy.

Artifact quality items were eventually introduced through various in-game events, such as Halloween 2006 and the Ophidian Invasion. Quests also introduced new Artifact quality items, such as the Truth and Redemption quest, which granted The Redeemer as a reward. For UO's 10th anniversary in 2007, a drop system similar to the Paragon system was introduced in the Anti-Virtue Dungeons, which brought with it a new set of Virtue themed artifacts that did possess the Artifact Rarity property.

Recent artifacts, like the Stygian Abyss Artifacts and the High Seas Artifacts have reverted to not having the Artifact Rarity property. This is also true for the new Artifact quality dungeon loot system in Covetous, Despise, and select other dungeons.

Standard Artifacts

Items which possess the Artifact Rarity item property can be classified into several categories.

Artifact Quality Items

Artifact quality named items which do not posses the Artifact Rarity property.

See also