Ismantrop is an ancient fortress, which was used probably between years 300-500 AD. The ringfort consists of a limestone wall approximately 300 meters long and has nine gates. Inside the ringfort were 95 houses arranged in 12 blocks around a central open area with a circular building. Ismantorp is the largest and probably the oldest of the ringforts on Öland.
The first written description of Ismantorp dates back to the year 1634. Renowned botanist Carl von Linné, as well as other travellers and scholars, paid attention to the fortress. Researchers have tried to determine the fortress's age, function and history since the 19th century. Its well-preserved walls distinguish the fortress, as do the central building's unusual location on a ground elevation, the 88 visible house foundations and the nine gates.
Theories of Ismantorp's function differ widely. The fortifications suggest a defensive purpose, but its many gates make is difficult to defend. Ismantorp fortress has been compared to large Slavic castles that were both protective fortress and religious sanctuaries. Other researchers view the fortress as an integrated part of a united defence of the island of Öland.
Ismantorp, which today is surrounded by marshes in the Mittlandskogen forest, is an archaeological enigma as well as a popular place to visit.
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.