On the death of his father in 1427, Ivan became Grand Prince. He kept good relationships with his large and powerful neighbours. In 1429, he attended the Congress of Lutsk and made Ryazan a vassal of the Grand Duchy of Lithuania under Vytautas. He signed a peace treaty with Vasily II of Moscow in 1447 and married his son and heir to Vasily's daughter. Near to his death he sent his two children to the court in Moscow for safety. It was during Ivan's reign that coins from Ryazan started to include the name of the grand duke.