The village is first mentioned in the history of Konstantinoupoli in 1453 (book b, chapter x). The name of the village Agios Ioannis comes from a temple devoted to Agios Ioannis Prodromos and is very common in the region of Kinouria since its residents from the 9-10th century have named their villages after Saints and built everywhere churches, chapels and monasteries. That's why Kinouria is called a replica of Agio Oros. It is widely believed that the local name Agiannitis derives from Aiginitis, due to the fact that people from Aigina were obliged to immigrate to Thirea in the years of the Peloponissean war (Thirea is the ancient name of the area of North Kinouria which includes Astros, Paralio Astros, Meligou, Haradro, Platano and Agios Ioannis). In the 19th century it was the largest village of the area. The people used to travel south during the winter only to pick up their olives and produce olive oil. After the Liberation from the Turks and since they were out of danger they started to make improvisations to the area and spend the winter there. This is when the name Astros or Astra became popular and Agios Ioannis was named Upper Astros. A winding road leads from Astros to the mountain villages of Kinouria. From this road you can enjoy the view to Paralio Astros and Mesogio Astros. On the left you can see the Monastery of Palaiopanagia, located deep in the mountain, built in the 13th century by the emperor Nikiforos Fokas which has unfortunately lost its former structure. Then you go past Ano Meligou and arrive at Agiannis in 5 minutes. In the entrance of the village you can see the church of Agia Paraskevi. Following the street you arrive at a small forest called Koutri where the visitor can see a marble stone, the inscription of the Karitsioti School, which survived the army of Ibrahim in 1826. The School had been rebuilt by Dimitrios Karitsiotis, a great trader and immigrant to Tergesti. It served as a boarding school and operated in 1798 with students from all over the Peloponesse. Another school was also built as a branch which now serves as a museum in Astros. About 250m after Koutri a visitor can see the big square of the village where the post Byzantine church of Saint George is. The temple is decorated with works of Georgios Kolidas, a painter and priest who came from the village. Near the square there is a two storey rectangular building which according to the tradition was used as a governmental building for the revolutionary government, from August 22nd to October 1st 1822, a fact confirmed by the Files of Lazaros and Georgios Kountouriotis. Going down from the square to the southern part of the village you go past Koufovouno, where you can see the renovated mansions of Anagnostis Papazoglou, and reach the spring Pigadaki (Little Well) with the inscription dated back to 1100 A.C which says " Officer Hatzi-Ismahil, a sensitive person and peacemaker himself, leaves this source of crystal-clear and sweet water for people's sake. For this life-giving act of his say your Fetiha (prayer)". A bit downwards you can see the church of Saint John, one of the post-Byzantine era as well. The visitor can admire the trees and the plentiful, cold water which springs from the church and flows in four canals. Until about 1960 the water used to flow into four windmills and water the gardens. Unfortunately now the place has almost been deserted and is full of bushes. You can go eastwards, in the southern part of the village, go past the old school, the chapel in the place of the church of Agios Vasileios, which was also burnt down by Ibrahim, and reach the most famous spring of Soulinari, which adorns the area. ‘'In Agiannis there is a spring, called Soulinari, And whoever is in love, can go, drink and heal" or "My little girl from Agianni, you have burnt my little heart" From the church of Saint George, there is a street which leads to the upper part of the village as well as to Laka, the second square, where the temple of Holy Mary stands, built by the Papoulias brothers on the base of the older temple destroyed by Ibrahim. From this point everyone can admire almost the whole village, the greenery and the wild beauty of the surrounding mountains. The street goes on and leads to the village exit towards the monastery of Malevi and the village of Agios Petros. When getting out of the village you should definitely stop at the spring of Perdikoneri with its splendid and digestive water. The Cultural Association of the village has created a place with sittings and a roof, creating this way an ideal place for a rest and a walk especially during hot summer evenings. About 2 kilometres from there, in ‘'Xerokampi'' you can see the ruins of the Oria castle, which dates back to the French conquest and its history is full if traditions, legends and songs. From the end of the 80s a building activity has started in Agiannis which goes on to the present and mainly concerns the renovation of old traditional buildings. It has been developed as a tourist resort of Astros especially in the summer and is a meeting place for tourists and locals. Apart from its natural beauty and its good, refreshing climate, Agiannis is only half an hour far from Astros beach. It has splendid taverns, where local meat and cheese are served along with local red wine. The visitor can enjoy moments of relaxation enjoying a sweet and a cup of coffee all seasons in the coffee shops of the square. Traditional fairs and cultural celebrations are also organized during the summer and mainly during the religious holidays of Agios Panteleimonas, Agia Paraskevi and Holy Mary. ‘' In Agiannis I loved a grouse, in Agiannis my heart is prisoned. I will get married to a girl from Agiannis, so as to die"