The biblical tale of the Tower of Babel offers a rather simple scheme: The world’s languages diversified at one defined moment, and before that moment everyone spoke one language intelligible to all. A similar simplicity seems to have seduced Karlgren, who assumed that the language spoken in Chang’an, the capital of Tang dynasty China, first spread over the whole territory of China, and that therefore all contemporary dialects without exclusion must have descended from this language, dating back to the beginnings of the 7th century AD.