Why did alexander continue his campaign after the goal had been achieved.

There were quite a few reasons. Allthough Alexander the Great already conquered was amounts of territory in Asia minor and Egypt, well outside the borders of Greece, there were always more riches to be found in different nations, together with bigger glory. As he was a general and a war-hero, it was important for him to obtain as much land as possible. 

Sir thomas more, venerated in the catholic church as saint thomas more, was an english lawyer, social philosopher, author, statesman, and noted renaissance humanist. he was also a councillor to henry viii, and lord high chancellor of england from october 1529 to 16 may 1532. i found this information on wikipedia