The foreign policy of Mary I, Mary Tudor, followed an expected pattern. Even before being crowned queen, Mary was known to be supportive of the Holy Roman Emperor and of the Habsburg family. Mary was a fervent Catholic, which further pusher her into the Emperorís camp as he had expressed his anger at the way the Church of England was becoming Protestant under Edward VI. The one country that Mary appeared to have no link with was France. Despite being a Catholic nation, France had the reputation of being a traditional enemy of England and Mary did little to buck this belief.
Maryís planned marriage to Philip of Spain, the son of the Holy Roman Emperor Charles V, cultivated even more the relationship England believed she had with the Holy Roman Emperor. However, there were those in England who cautioned against too strong an alliance with the Emperor, as they feared that this could only lead to war with France. However, those involved in trade were less concerned as part of the inheritance of Philip of Spain was the Netherlands and a marriage would, in their eyes, present far more commercial opportunities for them and even greater wealth.
Maryís marriage to Philip had with it safeguards to prevent England becoming involved in Spainís wars. However, one complicating factor was that the marriage alliance did state that Philip should aid Mary in governing her kingdom. This gave Philip a loophole with which to drag England into conflicts that concerned Spain alone.
1555 proved to be a decisive year in Maryís reign. By this year it was assumed by many that Mary would not provide a child for the succession. In October 1555, Charles V abdicated and gave over his land to Ferdinand (Germany) and Philip (Spain, the Netherlands, Naples and the New World). Maryís most trusted advisor, Stephen Gardner, died in November 1555.
In March 1556, Philip persuaded Mary to support Spain in a war against France. The Privy Council knew that England could not afford a foreign war but reluctantly agreed to declare war on France.
While the war went well for the Earl of Pembroke, who led the English army, the same was not true for the garrison at Calais. While Pembroke was involved in a decisive battle against the French at St. Quentin in 1557, a French force defeated the English garrison at Calais, which fell on January 13th 1558.
The loss of Calais was a humiliating blow for the English government. It managed to find the money to finance an army of 7,000 soldiers and 140 ships. However, rather than attack Calais, the force attempted to take Brest. They found that Brest was too heavily defended and captured a much smaller port, Le Conquet, instead.
Many expected a decisive battle between Henry II and Philip II. Instead, both men preferred to negotiate a settlement. The death of Mary in November 1558 took England out of the equation. The Treaty of Cateau-Cambresis of April 1559 between Spain and France was meant to be the start of lasting peace between the two.
Maryís foreign policy brought little credit to England. She relied too much on her Spanish advisors, who worked to better the position of Spain as opposed to England. There is little doubt among historians that Philip used his marriage to advance the cause of Spain with no thought as to the impact of his policies on England. It was hardly surprising that after the death of Mary, that Philip no longer saw England as an ally.