Deza is a town in Soria in the community of Castilla y León. Human settlements have been found in the area since the Upper Paleolithic.
The Titos (an ethnic group included among the Celtiberians) and later the Romans also settled in the current Deza. During Arab domination, Dassa was an important fortification controlled by the Berbers, as the border between the Christian and Muslim kingdoms was in the nearby Douro.
Among its historical heritage, the parish church of Nuestra Señora de la Asunción stands out, from the 16th century, with a tower from the 17th century, and also the main civil building, the strong house of the Fernández de Abarca family, where the town hall is currently located. Deza has a bullring, the oldest in the province in its original location, dug into the earth.