 At home, Tsarina Marie Alexandrovna was suffering from tuberculosis and was spending increasing time abroad.In 1866, Alexander II took a mistress, Princess Catherine Dolgorukaya, with whom he would father three surviving children.The affair, in the face of the tsarina's declining health, served to alienate the rest of his adult children, save his son Alexei and his daughter, who, like Alexander II's brothers, believed that the tsar was beyond criticism.