Fifteen kilometres from Kilkis lies the village of Palaio Gynaikokastro, known mostly from the stone ruins of its castle. This castle was so named because it was so well fortified that even women could defend it. Another tradition says that during the Turkish siege in 1383 commander of the Byzantines was a woman, Maroulia, so the castle was named by the Turks Avret Hisar, namely Women’s Castle. Since its establishment it operated as a bastion of Thessaloniki aiming to strengthen its defence against the raids of the Serbs, Tatars and Bulgarians from the north. It is just 45 kilometres from Thessaloniki and oversees the area between the rivers Gallikos and Axios. The hill on which stands the castle has a height of 200 meters and a total area of 25 acres surrounded by stone walls. At the top of the castle there is a tower and on the west a pit with a diameter of 2 meters and a depth of 28 meters. Many stories are told about it. It is said that its depth reaches 70 meters, that in 1922 there was a wooden floor to its bottom or a gallery serving as an emergency exit. The castle was founded by Emperor Andronicus III Palaeologus between 1328-1341 for the defence and protection of settlements in the area from barbarian invasions. It was a strong fortress with Byzantine officials. In the summer of 1342 the castle gave refuge to the Governor of Thessaloniki, protostrator Theodoros Synadinos, followed by one thousand aristocrats, when in danger because of a popular uprising, the same was also the case with Kantakouzinos and his soldiers. In 1384, Gazi Evrenos conquered Gynaikokastro and destroyed it.