How did Blue and White ceramics transition from China to Europe?
Turns out they didn't. Blue and white ceramics originated in Iran and spread across the middle east and eventually made it to China. China developed a new style as they were able to fire their glazes at a higher temperature for porcelain. This changed the colour slightly as they were able to burn out arsenic and some of the manganese. China eventually discovered their own deposits of cobalt, but were dependent on imports from Iran for many years. The lighter, stronger porcelain transitioned out of China into Europe along the silk road. It resulted in the revival of Blue on White popularity and the many duplication of patterns onto heavier earthenware. This Asian-appropriation was adopted by the Dutch in their manufactories and given a more European theme (Delft) while the Italians went down the multi-colour path of majolica. Turkey meanwhile, developed their classic red, blue, turquoise of the Iznik style.
The next research question to be answered (it's a two parter):
Why Iran and Why Kashan?
What was it about Kashan that permitted the production of such a large number of tiles? Was it geology, geography or political?
Where did the cobalt actually originate from? There are a number of geological settings that could produce cobalt ores. How was it refined?