The city of Soria formed in a valley near the castle that defended the Douro Riverbanks on the border between the Crowns of Aragon and Castile. The city was destroyed towards the end of the 12th century when Sancho of Navarre attacked it, therefore a great defensive wall was built to prevent further destruction. The wall defended a surface of 100 hectares that went from the Douro River up to the pastureland known as “La Dehesa”, and also from the castle up to the hill where you can find the Chapel of El Mirón.
The Sorian wall was destroyed by General Durán at the end of the Spanish Independence War to avoid French troops from entrenching in the castle. This is the reason why there are so few remains of this castle and why we can only see part of the tower and some parts of the defensive walls. From the castle, you can see a 360º view of the city and the bridge that crosses the Douro River, and in the Chapel of San Saturio, you can see frescos depicting the castle as it once was.
References:Celje Castle was once the largest fortification on Slovenian territory. The first fortified building on the site (a Romanesque palace) was built in the first half of the 13th century by the Counts of Heunburg from Carinthia on the stony outcrop on the western side of the ridge where the castle stands. It had five sides, or four plus the southern side, which was a natural defence. The first written records of the castle date back to between 1125 and 1137; it was probably built by Count Gunter. In the western section of the castle, there was a building with several floors. Remains of the walls of this palatium have survived. In the eastern section, there was an enclosed courtyard with large water reservoirs. The eastern wall, which protects the castle from its most exposed side, was around three metres thicker than the rest of the curtain wall. The wall was topped with a parapet and protected walkway.