Since the failure of Somerset's schemes, ten years before, Scotland had remained under French influence, with Mary of Guise, the widow of James V, as regent. Scotland was a turbulent kingdom, inhabited, except in the cities of the south, by a half-civilized folk, and disturbed by the feuds of rough clan leaders and border barons. It was this discontent that, about the middle of the sixteenth century, made easy the introduction of the reform movement. Beaton, bishop of St. Andrews and leader of the old church party, fought the new ideas and caused about forty persons to be put to death. Not until 1559, when John Knox, one of the most determined of Calvin's followers, returned to Scotland from Germany, where he had been a leader of the Frankfort church, did the Scotch reformation break out in real earnest. Roused by the fiery preaching of Knox, the Scotch people in a frenzy of excitement accepted the new teaching and began to tear down and destroy altars, churches, and other monuments of the old faith. Mary of Guise appealed to France for aid, while the Protestant lords of the congregation turned to Elizabeth.
Cecil saw his opportunity. Knowing that Philip would not raise a hand to make the French queen, Mary Stuart, queen of England, he turned from the Archduke Ferdinand, and having proposed a marriage between Queen Elizabeth and the earl of Arran, heir apparent to the Scottish throne, sent a fleet bearing infantry and cavalry to besiege the French at Leith on the Forth. The effort proved entirely successful. The English were victorious. This event, coupled with the death of Mary of Guise in June, 1560, made possible the signing of the treaty of Edinburgh the next month. This treaty provided for the retirement of the French troops, the destruction of the fortresses of Leith and Dunbar, and the accession of Mary Stuart as queen of Scotland, provided she abandon her claim to the English throne, acknowledge Elizabeth as rightful queen of England, grant a constitution to her subjects, and agree that no foreigner should hold office nor ecclesiastic control the revenues in Scotland.
Had Mary accepted the terms of the treaty of Edinburgh, French influence in Scotland would have come to an end then and there. But she refused to accept them, and the treaty was signed only by the Scottish lords. The agreement was, however, a victory for Cecil and Elizabeth, and marked an important step toward the resumption of friendly relations between England and Scotland. The work of reform in Scotland was completed in 1561 by the establishment of the kirk, the adoption of the Protestant faith as defined by John Calvin, the dissolution of the monasteries, and the seizure of the monastic lands. Another bond now existed between the two countries, for thenceforth both England and Scotland were Protestant kingdoms.
In the autumn of 1560 Cecil's position was a strong one. His chief opponent, Robert Dudley, Earl of Leicester, whom many thought that the queen wished to marry, was temporarily in disgrace, suspected, though probably unjustly, of murdering his wife, Amy Robsart. Leicester had taken the side of France, and for twenty years labored in vain to thwart Cecil and his policy. Toward the end of 1560 the situation underwent another change. The death of Francis II in December gave great joy to the Protestants, because it brought to an end Mary Stuart's reign as queen of France and consequently weakened the influence of Mary's relatives, the Guises, who were the leaders of the extreme Roman Catholic party in France. It relieved the mind of Elizabeth by removing all danger of a French invasion by way of Scotland. At the same time it pleased Philip also, for he had no further need to dread a union of France and Scotland under a single head; and it did not discourage the English Catholics, who now expected Philip to support the claim of Mary Stuart to the throne of England, as a means of making England a Catholic state.
Cecil foresaw the new difficulty and attacked Philip on his religious side by raising the spectre of a Protestant league. He looked with favor upon a proposal made by the Protestants that Elizabeth should marry the Protestant Eric XIV, King of Sweden. He invited Mary Stuart to return to Scotland and place herself in the hands of the Protestants there. He despatched the duke of Bedford to France to consult with the Huguenot leaders, and another emissary to the Protestant nobles of Scotland, thus making it appear that Elizabeth was about to become the leader of a Protestant league in Europe. At the same time he proceeded against the Catholics in England for attending mass, refused to admit into England a papal legate who was coming to invite Elizabeth to send deputies to the Council of Trent, and spread the report that the Catholics were engaged in a conspiracy against the queen. Cecil had chosen his time well. Philip was confronted with disaffection in the Netherlands ; the Turks were advancing westward in the Mediterranean, and the Spanish treasury was empty. His efforts succeeded. Philip was frightened, and the Catholics in England, giving up hope of help from Spain, turned to Mary Stuart as their champion.