The Portuguese dependencies on the eastern coast of Africa below the Zambesi were already exhibiting all the marks of decrepitude and decay. The Portuguese nation was almost exhausted, the blood of the peasantry in its southern provinces had become degraded, and the chief sources of its wealth were for ever lost. This condition of things in the kingdom itself was reflected in its dependencies over sea, and in none of them to a greater extent than in those treated of in these volumes.

King Joao IV, the first monarch of the house of Braganca, died on the 6th of November 1656, leaving a son named Affonso, only thirteen years of age, heir to the throne. The queen dowager, a woman of unusual ability and force of character, then became regent, and held that office until the 21st of June 1662, when Affonso VI became king. His sister, Catherine of Braganca, only a few weeks before had been married to Charles II of England. A close connection between the two countries was thus commenced, which was of great advantage to Portugal by giving her assistance in her war with Spain, and which led some years later to important commercial arrangements. For more than a quarter of a century Spain strove to suppress what was termed at Madrid the rebellion of the duke of Bragança, but at length a series of victories gained by the Portuguese with the assistance of their foreign friends made the attempt hopeless, and on the 13th of February 1668 peace was concluded by a treaty in which the independence of Portugal under the sovereigns of her choice was fully recognised.