Mary de Guise, also known as Mary de Lorraine was born on November 22, 1515, she died in Edinburgh on June 10, 1560. She was the eldest of twelve children of Claude de Lorraine and Antoinette de Bourbon and was the older sister of Francois de Lorraine also known as Francois de Guise (Duc de Guise), Charles de Lorraine (second Cardinal de Lorraine and first Cardinal de Guise), and Louis I de Lorraine (second Cardinal de Guise).
Mary de Guise became a widow in 1537 after a year of marriage to Louis II d'Orleans, the second Duc de Longueville. She refused to marry Henry VIII, King of England, but to the urgings of Francis I, King of France, she consented to marry James V, King of Scotland on May 9, 1538. James V's first wife, Margaret of France had died the year before. Thus Mary became the Queen of Scotland. She one daughter on December 8, 1542 with James V, named Mary Stuart, a week later on December 14, James V died and James Hamilton, second Earl of Arran became regent for her daughter.
Taking advantage of this regency, Henry VIII sought to establish an anti-Catholic influence in Scotland and to this end on March 12, 1543 he made a treaty with James Hamiltion which betrothed Mary Stuart to marry Edward, later Edward VI. However, after the death of her advisor the Cardinal Beaton, Mary looked to France for the support of a Catholic policy and it was decided by the Estates of Scotland, after appealing to them that on February 5, 1548 Mary Stuart should be sent to France, Scotland's oldest and most faithful ally. After the outbreak of war with England, Mary de Guise arranged for the betrothal of her daughter to be married to the young Dauphin Francis, son of Henry II, king of France. In 1554 with the aid of the French, Mary de Guise replaced James Hamilton as regent and she made no secret of her desire to bring France and Scotland together.
While the Reformation was occurring in Scotland, Mary de Guise maintained her authority through the advice and assistance of her brothers Francois de Lorraine and Charles de Lorraine. Her brothers kept her informed of the great success achieved by her daughter, Mary Stuart.
"She rules the king and queen."
~ Charles de Lorraine.
On the marriage between the Dauphin Francis and Mary Stuart, Henry II, king of France wanted the two to assume the titles of King and Queen of England and Scotland. He alleged that Elizabeth, later known as Elizabeth I, daughter of Henry VIII and Anne Boleyn was ineligible having been the child of an illegitimate marriage also branding her as a heretic.
The Guise's hoped that the Catholic policy that they had established earlier would establish a Catholic rule throughout Britain. Nicholas de Belleve, Bishop of Amiens, and several doctors of the Sorbonne went to Scotland in 1559 to prevail upon Mary de Guise to put on trial all non-Catholic ecclesiastics. Protestantism was spreading rapidly in Scotland and although Mary de Guise wrote to her brothers that the only means of preserving the Catholic religion in Scotland was to allow complete liberty of conscience, she dared not oppose the order from France. She began a great campaign of suppression. In 1559, John Knox led the Protestants against Mary de Guise pillaging churches and monasteries entering Edinburgh and declared by the right of insurrection against tyranny, and the assembly of the peers and the barons of the kingdom declared her deposed from the regency on October 21, 1559. At this time she was at Leith guarded by a troop of French soldiers, they overcame the Protestant troops and she was able to enter Edinburgh, but an English army sent by Elizabeth and the assistance of the Protestant allys proved the stronger force. The war ended shortly after Mary's death by the Treaty of Edinburgh in 1560. This ended the French domination of Scotland and opened the way for the Protestant church in Scotland.
Sources: Catholic Encyclopedia, Encyclopedia Brittanica, World Encyclopedia.