Strellin was a Grade 3 planet, as labeled by the Galactic Census Bureau, inhabited by humans in a medieval society and known for its "peaceful tranquility". Other native life included the Vulteen and Brandelak. The Brotherhood of the Black Petal lived in a mountainous region of the planet, and guarded a valley where the last of Ostrecallis Mediosai, known as the Dream Flower, grew, having drifted to Strellin on solar winds from the Ostrecallis system after it went meganova.
A Black Dalek and several Daleks of the Emperor's Personal Guard crashed on Strellin while travelling from Kantra to Skaro, and were cared for by the Brotherhood of the Black Petal. They attempted to use the Dream Flower to conquer the universe, but were defeated with the help of the Sixth Doctor and Constance Clarke. (AUDIO: Order of the Daleks)