The Fortress Tower of Baños de Rioja was one of a series of fortresses that were scattered throughout the upper Rioja region to protect against raids and sieges at the time. At the beginning of the year 1200 (13th century), the López de Haro family, owners of the lordship of Vizcaya and founders of the town of Bilbao, ordered the construction of this fortress in Baños de Rioja. It originally had two towers, a wall, moat and defensive bastions and was topped with battlements.
The keep, which is the one that remains standing today, has been declared a historical heritage site under Law 16/1985. Its characteristics correspond to the prototype of the Gothic tower in the region. It has thick ashlar walls (1.70 m thick), a rectangular floor plan (9.75 x 8 m), and is 19 m high. It still has all of its original arrow slits on the ground and second floors, windows with semicircular arches with stone seats on the sides on the first and third floors, and windows with mullioned windows on the fourth floor, as well as part of the mullioned windows of the defensive balcony on the first floor.
Diego López III de Haro was the grandson of King Alfonso IX, and was known as the King of Baños de Rioja, as he died in this town in October 1254, due to the rheumatic problems he was suffering from, either because he got into a bath with water that was too hot, or because of the carelessness of a servant who set fire to a sheet dipped in sulphur. He was buried in the Monastery of Santa María la Real de Nájera, next to his father Lope Díaz II de Haro.
The Torre Fuerte now houses tourist accommodation, as its current owners, after years of restoration and rehabilitation work, have managed to make this symbolic and beautiful building, full of historical value, available for visitors to enjoy.