This expansion was mainly at the expense of Spain; but at first Spain was regarded as Elizabeth's friend, not France. France had a rival candidate for Elizabeth's throne in Mary Stuart, the wife of the dauphin who soon (1559) became king as Francis II.; and Spanish favour was sought to neutralize this threat. Fortunately for Elizabeth, Francis died in 1560, and the French government passed into the hands of Catherine de' Medici, who had no cause to love her daughter-in-law and the Guises. France, too, was soon paralysed by the wars of religion which Elizabeth judiciously fomented with anything but religious motives. Mary Stuart returned to Scotland with nothing but her brains and her charms on which to rely in her struggle with her people and her rival. She was well equipped in both respects, but human passions spoilt her chance; her heart turned her head. Elizabeth's head was stronger and she had no heart at all. When Mary married Darnley she had the ball at her feet; the pair had the best claims to the English succession and enjoyed the united affections of the Catholics. But they soon ceased to love one another, and could not control their jealousies. There followed rapidly the murders of Rizzio and Darnley, the Bothwell marriage, Mary's defeat, captivity, and flight into England (1568). It was a difficult problem for Elizabeth to solve; to let Mary go to France was presenting a good deal more than a pawn to her enemies; to restore her by force to her Scottish throne might have been heroic, but it certainly was not politics; to hand her over to her Scottish foes was too mean even for Elizabeth; and to keep her in England was to nurse a spark in a powder-magazine. Mary was detained in the hope that the spark might be carefully isolated. Rebellion of 1569 and excommunication of Elizabeth. Plots against Elizabeth. Relations with France and Spain.