The band was founded in Cracow, in 1999. The same year their first demo, Art of Decadence, appeared. It consisted of four tracks plus a bonus - cover version of Madonna’s "Frozen" (performed with Anna Wojtkowiak from Centuria).

As the demo was very warmly welcomed on the underground scene the band decided to continue their musical activity.Also in 1999 Thy Disease won the second prize at Metal Millenium Party and Vader invited them to play as a support act on their Polish tour.

In September the band recorded a promo tape with 2 brand new tracks ("Cursed" and "Crashing the Soul") and re-mastered versions of pieces known from the demo ("Art of Decadence", "Finding God", "Frozen", "Eternal Disease", "The Earth").

In January 2001 the band signed a long-term deal with Metal Mind Productions and entered the studio to record their first full-length Devilish Act of Creation. The album was distributed in all Europe and also in Japan, USA and Canada.

In April 2001 "Frozen" hit the second position on Radiostacja metal charts Rotten Ten.Readers of Metal Hammer magazine voted Thy Disease the best Polish metal group of 2001. In similar rankings in Mystic Art and Thrash’em All they won respectively third (Debut of the Year) and sixth position.

In March 2002 the band played at Metalmania, with such bands as Paradise Lost, Cannibal Corpse, Moonspell, Tiamat or Flowing Tears. In May 2002 Pinochio left the band and Alizee666 joined the group as a new drummer.

Metal Mind signed a license deal with South Korean label KMD (for Devilish Act of Creation release in South Korea).In September the band entered Yaro Home Studio to record their new album Cold Skin Obsession.

A video to "Perfect Form" was featured on Various Artists "Ultimate Revenge" DVD - a unique guide to Polish death / black metal scene.In October the band had a chance to support Decapitated, Krisiun and Vader in Cracow.

During the next couple of months the band focused on promoting the new material (in Europe, USA, Canada, and Peru, among others). The album took 9th position on Legacy Magazine charts (December 2002).

"Perfect Form" video was aired in Polish VIVA tv and stayed on VIVA Rock Charts for a few weeks (at 10th, 8th and 6th position).Thy Disease musicians also perform in:Anal Stench (brutal death metal - Yanuary & Psycho, with guys from Decapitated, Sceptic, Crionics, SerpentiaCrionics (black metal) - Alizee666 & Marco’ticDelight (gothic metal) - CubeDiscography:Art Of Decadence, 2000, DemoDevilish Act of Creation, 2001, Full-lengthCold Skin Obsession, 2002, Full-lengthExtreme Obsession Live, 2004, DVDNeurotic World Of Guilt, 2004, Full-lengthRat Age (Sworn Kinds Final Verses), 2006, Full-lengthAdditional notes:In December 1999 THY DISEASE won the second prize on "Metal Millenium Party" - metal contest for new talents in Krakow.