The Asclepeion, also known as the Asclepius sanctuary, which sits at the southern slope of Acropolis was unknown until a few years ago, now it is being restored. This reports the Archaeology News Network. The study for the restoration was presented to the Central Archaeological Council and was approved unanimously.

In ancient Hellas and Rome, an asclepeion (Asklepieion, Ἀσκληπιεῖον) was a healing temple, sacred to Asklepios. These healing temples were a place in which patients would visit to receive either treatment or some sort of healing, whether it was spiritual or physical. Starting around 350 BC, the cult of Asclepius became increasingly popular. Patients flocked to asclepieia to be healed. They slept overnight ('incubation') and reported their dreams to a priest the following day. He prescribed a cure, often a visit to the baths or a gymnasium. Since snakes were sacred to Asklepios, they were often used in healing rituals. Non-venomous snakes were left to crawl on the floor in dormitories where the sick and injured slept.

The asclepieion located on the south slopes of the Acropolis of Athens dates back to around 420 BC.
The ruined building wasn't discovered until 1993, when research led architect Rosalia Christodoulopoulou to discover piles of architectural parts and building debris. Christodoulopoulou told the AMNA news agency:

"Breaking down these piles of stones we began to distinguish specific groups. However, we didn’t know where all those materials belonged. Research took five to six years until we discovered two stones from a corner that matched the building's foundations.

We quickly realized that all the remaining pieces were part of the temple because they had the same design and were made from the same variety of marble.

In 2011 we found two pieces under the first entry step which gave us new information that changed the initial hypothesis. Research continues because we found parts that have been treated or re-used many times so it is difficult to identify."

A total of 450 architectural parts found in the stone piles have been thus far identified. Athens Polytechnic Professor Manolis Korres who oversees the preservation of the Acropolis monuments said:

"It was a monument that existed only on paper and was considered lost as a building. Now, thanks to Rosalia’s work, there is plenty of material. This is very important for the topography of the southern Acropolis slope. All the marbles are there."

The first sanctuary was built in 420-419 BC, an era from which no remains have been found. A second temple was built on top of it during the 1st century BC, probably after 86 BC, Christodoulopoulou noted.

“We are restoring the second phase, a repair and expansion to the east that took place in the 3rd century AD, after the Heruli raid (267 AD) during which many Athenian monuments were destroyed."

The restoration will continue and the first phase--the restoration of the base of the walls--will be completed by the end of the year.