San Esteban de Deyo, also called the Castillo de Monjardín, is a ruined castle on a hill overlooking Villamayor de Monjardín in Navarre. The castle lies at an elevation of 890 metres. The castle has a Roman foundation, but was repeatedly rebuilt over the centuries. It was one of the last fortresses of the Banu Qasi, the local Muslim dynasty, before it was taken by King Sancho I of Navarre in 914. According to the Historia Caroli Magni et Rotholandi, the castle was actually taken by Charlemagne from a Navarrese prince named Furré. Only the walls of the castle stand today. Many of the stones were taken to build a Baroque hermitage, the Ermita de San Esteban, in the 17th century.
References:The ancient Argos Theater was built in 320 BC. and is located in Argos, Greece against Larissa Hill. Nearby from this site is Agora, Roman Odeon, and the Baths of Argos. The theater is one of the largest architectural developments in Greece and was renovated in ca 120 AD.
The Hellenistic theater at Argos is cut into the hillside of the Larisa, with 90 steps up a steep incline, forming a narrow rectilinear cavea. Among the largest theaters in Greece, it held about 20,000 spectators and is divided by two landings into three horizontal sections. Staircases further divide the cavea into four cunei, corresponding to the tribes of Argos A high wall was erected to prevent unauthorized access into the theatron and may have helped the acoustics, but it is said the sound quality is still very good today.
Around 120 CE, both theaters were renovated in the Roman style.