Saint Isaac's Cathedral of Isaakievskiy Sober is the largest Russian Orthodox cathedral in the city, and was the tallest Eastern Orthodox church upon its completion (subsequently surpassed only by the Cathedral of Christ the Saviour). It is dedicated to saint Isaac of Dalmatia, a patron saint of Peter the Great who had been born on the feast day of that saint.Features Creative Play. Simulative Hand-Eye Coordination. Beautiful Display. Pieces - 105. Dimension - 13 L x 9 W x 2 H in.