It is the round tower of the southeast corner of the castle of Didymoteicho, which is known by this name because of the legend of the suicide of the emperor's daughter. It is probably an early Christian construction, which underwent extensive repairs in the first half of the 14th century. It bears on its surface an inlaid plate with an engraved monogram with the characters T-P-X-S.

According to legend and tradition, during the siege of Didymoteicho by the Ottomans, the king left the city to hunt. The Ottomans found out about it and took advantage of it to capture the impregnable castle. They dressed a young boy as a monk, who stood in front of the West gate and asked the king's daughter to open the gates for him to pray inside the castle. The Ottomans, hidden as they were in the forest, took advantage of the queen's response and rushed to the open gates. The queen, realizing her great mistake, climbed the highest tower of the castle and committed suicide by jumping from it.