So the history is actually really well described in crpgaddicts blog. First there was wizardry (basically all rpgs both in the us and japan are descendents of wizardry, some with the mixture of ultima). bard's tale is a wizardry clone (its wizardry in a city). Dungeon master is an attempt to make a better wizardry, taking advantage of the mouse and the amiga's graphics (its basically wizardry in real time). EotB is a dungeon master clone.