On February 10, 1525, Charles V.`s younger sister, Katharina of Austria, married John III of Portugal and on 11 March 1526 Charles V married the sister of King Johann Isabella of Portugal. These cross-marriages strengthened the ties between the two crowns and facilitated an agreement on the Moluccas. It was in the emperor`s interest to avoid conflict so that he could concentrate on his European policy, and the Spaniards did not know how to obtain spices from the Maluku Islands to Europe by way of the East. The Manila-Acapulco line was not set up until 1565 by Andrés de Urdaneta. Other problems related to the imperial expansion of Spain and Portugal forced an agreement. The transaction was arranged by the Treaty of Zaragoza in 1529, facilitated by the marriage of Charles V to Isabel of Portugal, which strengthened relations between the two courts. The contract of Tordesillas (1494) had brought only a fixed-term agreement. As soon as a passage on the American continent (through the strait that Ferdinand Magellan found in 1521) was discovered and an alternative sea route to the Spice Islands was discovered, another conflict emerged between Portugal and Spain: the identification of the anti-antimeridien, the line on the other side of the world, corresponding to that created by the Treaty of Tordesillas. The Treaty of Zaragoza (April 5, 1529) confirmed D. Joo III of Portugal in the achievements of D. Joo II in Tordesillas: The interests of Charles V, the Holy Roman Emperor of the German nation, overrided the interests of D. Carlos I, Rey- 95-Castilla. Charles, who was deeply involved in European wars and politics and who, as always, desperately needed hard money, was smart at reducing his losses; and in the face of French piracies and threats against Brazil and Guinea, D.
Joo was also ready to settle down. The main provision of the treaty was that a pole-to-pole demarcation line should be adopted, defined by the storage of 19 degrees on an E-deposit of the Moluccas; Beyond this line (which is actually, then of course not known, Portugal gave about 187 degrees in length against Spain 173 degrees) the King of Castile should not claim to negotiate, or sail. There was a leak clause that could hardly be considered a pro forma that preserves the face: if future investigations were to establish precisely that the Moluccas were east of the true antimeroid of the Tordesillas line, the agreement would be null and void.