CHAPTER XXII. THE REIGN OF CATHARINE I., ANNE, THE INFANT IVAN AND ELIZABETH. From 1725 TO 1769. Energetic Reign of Catharine .-- Her Sudden Death .-- Brief Reign of Peter II .-- Difficulties of Hereditary Succession .-- A Republic Contemplated .-- Anne, Daughter of Ivan .-- The Infant Ivan Proclaimed King .-- His Terrible Doom .-- Elizabeth, Daughter of Peter the Great, Enthroned .-- Character of Elizabeth .-- Alliance with Maria Theresa .-- Wars with Prussia .-- Great Reverses of Frederic of Prussia .-- Desperate Condition of Frederic .-- Death of Elizabeth .-- Succession of Peter III..