Passage: The lands to the east would belong to Portugal and the lands to the west to Castile. The treaty was signed by Spain, 2 July 1494, and by Portugal, 5 September 1494. The other side of the world was divided a few decades later by the Treaty of Zaragoza, signed on 22 April 1529, which specified the antimeridian to the line of demarcation specified in the Treaty of Tordesillas. Originals of both treaties are kept at the  General Archive of the Indies in Spain and at the Torre do Tombo National Archive in Portugal.This treaty would be observed fairly well by Spain and Portugal, despite considerable ignorance as to the geography of the New World; however, it omitted all of the other European powers. Those countries generally ignored the treaty, particularly those that became Protestant after the Protestant Reformation.

Question: What treaty is mentioned which contains the last letter of the English alphabet?
the Treaty of Zaragoza