The Coldharbour Compact was an agreement between the Tribunal god Sotha Sil and eight powerful Daedric Princes: Azura, Boethia, Hermaeus Mora, Hircine, Malacath, Mehrunes Dagon, Molag Bal, and Sheogorath. The Compact was created in response to the destruction of Gilverdale by Molag Bal. It was made between the 3rd and 5th of Rain's Hand, 1E 2920 when Sotha Sil entered Coldharbour from Artaeum's Dreaming Cave.
Little is known about the Compact but it is theorized that it prevents the Princes from directly manifesting on Nirn. It is also speculated that, in order to secure the agreement of the Princes, Sotha Sil either made a credible threat to them or presented a significant offer in exchange. According to Hermaeus Mora's Seekers, the prince made a pact with every mortal on Nirn to cease all direct interposition in Mundial affairs, and for his agreement it seemed he was paid a great price, something he dearly desired. The compact appeared to bind in both directions, resulting in mortals no longer coming to Apocrypha.
Mehrunes Dagon himself leads credence to the idea that Sotha Sil spoke of a consequence to violating the pact. Despite agreeing to it, Mehrunes Dagon arrived in Tamriel and destroyed the city of Mournhold just a few months later in Sun's Dusk of 1E 2920, before being banished by Almalexia and Sotha Sil. For breaking the truce, Dagon himself was broken on the soil of Mournhold.[UOL 1] After banishing him alongside Almalexia, Sotha Sil also slammed the planar doors between Nirn and the Deadlands shut, blocking off all access for Dagon as further punishment for breaking the Compact, and thus showing at least one punishment Sotha Sil could dish out for the Princes not holding up their end of the bargain.
The Compact did not bind Daedric Princes that were not present during the Compact, as the Daedric Triad composed of Clavicus Vile, Mephala, and Nocturnal attempted to remake Nirn in their image during the Daedric War of the Second Era. Mephala and Clavicus Vile would join a Compact with Sotha Sil circa 2E 582 after Nocturnal took control of the triad's plot, and aided the Psijic Order in stopping her from achieving infinite power. Much like the Coldharbour Compact itself, the specifics of the agreement are unknown. Furthermore, it is not even certain if they are considered to be the same Compact. 
The Compact did not prevent Molag Bal's attempted Planemeld in the Second Era nor did it stop Mehrunes Dagon from manifesting directly on Nirn in his true form during the Oblivion Crisis in 3E 433. It is possible that Sotha Sil's demise left nobody to enforce the Compact. It's also possible that the Compact was circumvented in these cases due to them being brought about by mortals (namely Mannimarco and Mankar Camoran).
- 2920, The Last Year of the First Era by Carlovac Townway — A fictional series of books about historical events involving Vivec and the Empire
- The Coldharbour Compact — A poem on Sotha Sil's mysterious First Era agreement with the Daedric Princes
- 2920, Rain's Hand — Carlovac Townway
- The Coldharbour Compact
- Sotha Sil's dialogue in ESO: Clockwork City
- Secrets Overheard in Apocrypha — Morian Zenas
- Mehrunes Dagon Lorebook Reading — Mehrunes Dagon
- 2920, Sun's Dusk — Carlovac Townway
- The Truth in Sequence: Volume 8 — Deldrise Morvayn
- Lyranth's dialogue in ESO
- Summerset Quest Line of ESO
- Events of ESO
- Events of Oblivion
Note: The following references are considered to be unofficial sources. They are included to round off this article and may not be authoritative or conclusive.