>>49788766 There was a territorial division during 1833 aimed at pleasing both the far left liberals and far right carlist absolutist (they failed, but the division stuck anyway). The dude they tasked to do so also took to grouping provinces by historical regions, pic rel. The territories that Castille conquered off the Taifa of Toledo way back during the reconquista got grouped together into what was dubbed "New Castille", while the territories before that particular conquest were dubbed "Old Castille".
This was all just as a way to group and classify provinces and served no gubernamental purpose though, he could just as well have divided the map into north, south, east, west and center Spain
Come 1978 after Franco's death, the government was reworking the territories and decided to group provinces (which had remained roughly the same as in 1833) into somewhat self-governing "autonomous communities", and reutilized those groupings giving them a new name: Leon and Old Castille (Castille-Leon) were merged together, and since there was no longer an Old Castille they had to rename New Castille to something else, so they dubbed it Castille-La Mancha after a major plateau and geographical area it encompasses. Also, the province of Madrid became it's own autonomous community separate from La Mancha, because "fuck you we're the government" or something I'd guess
