I won't bother with anything after the 0:25 mark, but the footage up to that point is from the 1963 Spanish film, El valle de las espadas, released in English as The Castilian. The movie chronicles the adventures of Fernán González, a 10th-century count of Castile (d. 970), and founder of a comital dynasty whose descendants would go on to rule as kings of Castile in the 11th century. As a result of the exploits of his successors, Fernán González would become a subject medieval legend, including a mid 13th-century epic poem. The real count was a power player in the politics of the Leonese and Navarrese kingdoms of northern Spain in the 10th century.

All the shots in the clip you've linked are from castles and churches in the Duero river valley in the modern day autonomous community of Castile y León.

The first castle is at Berlanga de Duero in the modern Spanish province of Soria. While impressive, it largely dates to the 15th and 16th centuries. The next castle, at around the 0:04 mark, is at Peñafiel in the province of Valladolid. While construction on a castle began in the 10th century during the rule of Fernán González, its current form is mostly the product of 14th- and 15th-century construction.

The first church, at the 0:15 mark, is Santo Domingo de Soria and dates to the second half of the 12th century with 16th-century renovations. The ruined cloister at the 0:20 mark is from the monastery San Juan de Duero, also in Soria, and dates to the 12th-13th centuries.

So little of what you see in the film would have been recognizable to Fernán González during his lifetime in the 10th century. Additionally, the area around Soria along the eastern reaches of the Duero River was part of a frontier zone still within the orbit of the Umayyad Caliphate. Soria was conquered by Alfonso I of Aragón in the 12th century. It was not a part of the County of Castile during Fernán González's lifetime.