Findings revealed that the Kurlan culture believed that an individual was part of a community of individuals; each of which had their own voice with their own desires as well as views of the world around them. This resulted in the creation of a form of art known as Kurlan naiskos.
The race's history were divided into numerous ages which included the Third Dynasty which was 12,000 years ago. Another age included the Fifth Dynasty. However, the Kurlan species would die several millenia before the 24th century. (TNG episode: "The Chase")
As it turned out, the Kurlans were really members of an ancient colony of Trill that lived on the planet. The colony was intended to be an all joined Trill community; however, a plague afflicted the symbiotes. The colonists, in order to try to stop the disease, and to improve the symbiotes, would genetically engineer the symbiont population which resulted in the creation of the parasites. (DS9 novel: Trill: Unjoined)
The Trill blockaded the planet in order to prevent the spread of the disease, and when it appeared that infected symbiotes would eventually escape, the Trill bombarded the planet; however, some of the altered symbiotes survived and as a result developed a hatred for their former brethren.