The ruins of ancient Sparta lie north of the modern city. It was a prominent city-state in Laconia in ancient Greece. Around 650 BC, it rose to become the dominant military land-power in ancient Greece.
Given its military pre-eminence, Sparta was recognized as the leading force of the unified Greek military during the Greco-Persian Wars, in rivalry with the rising naval power of Athens. Sparta was the principal enemy of Athens during the Peloponnesian War (431–404 BC), from which it emerged victorious after the Battle of Aegospotami. The decisive Battle of Leuctra against Thebes in 371 BC ended the Spartan hegemony, although the city-state maintained its political independence until its forced integration into the Achaean League in 192 BC. The city nevertheless recovered much autonomy after the Roman conquest of Greece in 146 BC and prospered during the Roman Empire, as its antiquarian customs attracted many Roman tourists. However, Sparta was sacked in 396 AD by the Visigothic king Alaric, and underwent a long period of decline, especially in the Middle Ages, when many of its citizens moved to Mystras.
Entering by the South Gate of the Acropolis, known as Lakedaemonia, there is the Rotunda, the Theatre and the Temple of Athena Chalkioikos to the West. Exiting the Acropolis by the North Gate there are the remains of the earliest ancient walls, the Heroon and the Altar of Lycourgos, whereas to the East there is the Sanctuary of Artemis Orthia. To the North is the Monastic Church of Osios Nikonas (10th 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.