and Ferdinand with the king of Hungary and his sister had been
arranged. Before he was twenty Charles himself had been engaged some ten
times with a view to political combinations. Naturally, therefore, he
regarded his near relations as diplomatic assets. The federative system
was equally familiar; Germany, the Netherlands, and even Spain, were in
a measure federations. Combining these two principles, he would within
his more immediate spheres of influence strengthen existing federations
by intermarriage, while he hoped that the same means would convert the
jarring powers of Europe into a happy family. He made it a condition of
the treaty of Madrid (1526) that Francis I. should marry his sister
Eleanor, Manuel of Portugal's widow, in the hope, not that she would be
an ally or a spy within the enemy's camp, but an instrument of peace.
His son's marriage with Mary Tudor would not only salve the rubs with
England, but give such absolute security to the Netherlands that France
would shrink from war. The personal union of all the Iberian kingdoms
under a single ruler had long been an aim of Spanish statecraft. So
Charles had married his sister Eleanor, much against her will, to the
old king Manuel, and then his sister Catherine to his successor. The
empress was a Portuguese infanta, and Philip's first wife was another.
It is thus small wonder that, within a quarter of a century of Charles's
death, Philip became king of Portugal.

In the wars with Francis I. Italy was the stake. In spite of his success
Charles for long made no direct conquests. He would convert the
peninsula into a federation mainly matrimonial. Savoy, the important
buffer state, was detached from France by the marriage of the somewhat
feeble duke to Charles's capable and devoted sister-in-law, Beatrice of
Portugal. Milan, conquered from France, was granted to Francesco Sforza,
heir of the old dynasty, and even after his treason was restored to him.
In the vain hope of offspring Charles sacrificed his niece, Christina of
Denmark, to the valetudinarian duke. In the long negotiations for a
Habsburg-Valois dynasty which followed Francesco's death, Charles was
probably sincere. He insisted that his daughter or niece should marry
the third rather than the second son of Francis I., in order, apart from
other reasons, to run less risk of the duchy falling under French
dominion. The final investiture of Philip was forced upon him, and does
not represent his saner poli