Goryeo
Taoism enjoyed its greatest popularity during the Goryeo Dynasty, especially in the court and the ruling class. Taoist court rituals were introduced into Korea from Song dynasty China, especially under King Yejong (r. 1105-1122). The object of worship in these rituals included most of the major and minor deities of the Taoist pantheon, but certain deities such as Samgye and T'aeil seem to have been the most popular.
By the mid period of the Goryeo Dynasty, Buddhism dominated Korea, subsuming other religions and philosophies, including Taoism.
Read more about this topic: Taoism In Korea