The Baltic Sea and its rivers, which were part of the legendary trade route «from the Varangians to the Greeks», also serve as the North-Western border of Russian land. It is no coincidence that here, starting in the 9th century, several powerful citadels were constructed: Staraya Ladoga, Koporye, Ivangorod and Vyborg Castle. Medieval architects tried their best to design defensive structures that blended in well with the local landscape. This served as a type of camouflage, with nature and its cliffs, steep riverbanks and the Finnish Gulf adding another element of defense. These historic fortresses, located on important and strategic grounds, were passed back and forth between countries and were improved along with the development of wartime tactics and strategy. How did Ivan III trick the Livonian Order? Where is was the Swedish king’s treasure hidden and why is Russian chainmail better than a knight’s suit of armour? Find out the answers to these questions and more in RTG’s new programme «Four fortresses. The battle for the borders of Rus».