Following the death of the sage Athorton of Nleeth in the Year of the Shattered Altar, 1264 DR, the priestess of Ilmater Beromchess Ilthyn covertly took the Tome of Torment—the holiest book of the Ilmatari faith—to the House of Holy Suffering. There, the senior Sage-Priest of the church, known as the Spontaer, studied the Tome. The Spontaer prayed to Ilmater for nearly a year, and received visions of powerful magical protections that would render the Tome usable only by priests of Ilmater. However, these protections would come at the cost of his life. The Spontaer explicitly requested that the Tome of Torment be delivered to the House of the Broken God in Keltar in Calimshan, the greatest temple of Ilmater, before he worked the magic on the Tome and sacrificed his own life.
However, against the Spontaer's wishes, Shrymaun Beldaerth refused to relinquish the Tome to the House of the Broken God. Archsufferer Bloirt Waelarn of the Keltar house declared all those of the "degenerate" Mussum house "heretics" and called for them to be cast out and treated as mentally ill. A few ambitious minor priests joined Waelarn and together they journeyed to the Mussum house, intending to "cleanse the filth". The priests of the House of Holy Suffering recruited the Companions of the Noble Heart paladin order to their defense, and attacked Waelarn and his followers, labeling them "false clerics" and "subverted by evil".
An angry Waelarn summoned three other knightly orders—the Holy Warriors of Suffering, the Knights of the Bleeding Shield, and the Order of the Golden Cup—to his side and vowed holy war against the "unclean ones of Mussum" and their allies. The war saw the violent clashes of Holy Hill Farm in 1266 DR and Bronsheir's Charge and Weeping Rock in 1267 DR. Finally, Lord Sir Jargus Holenhond of the Golden Cup called an end to the bloodshed between true believers, insisted that the Tome of Torment be transferred to Keltar as planned, and blamed Bloirt Waelarn for the senseless violence, determining that he should be removed from office and sent into hermitage for the remainder of his years. The weary paladins accepted and carried out his judgment.
Circa 1342 DR, however, the Tome of Torment had been stolen and hidden but then discovered by Kortolt Rushtyn, an underpriest of the House of Holy Suffering. Kortolt declined to take the Tome to either Mussum or Keltar, but instead to the shrine of Ravens' Rack west of Hlondeth, where he preached by himself.
After the Tome of Torment was stolen again in 1362 DR, the church of Ilmater offered a reward for its surrender at either the House of Holy Suffering in Mussum or the House of the Broken God in Keltar.
- Although Prayers from the Faithful states the House of Holy Suffering lies in Mussum from 1264 DR, the city of Mussum was actually abandoned as a result of plague in 472 DR and remained uninhabited, according to The Vilhon Reach: Dungeon Master's Reference (page 9). The House of Holy Suffering may therefore lie somewhere outside the ruined city, either remaining in use after Mussum's fall, or constructed later.