in 1946, the historian boris rybakov, while analysing miniatures of ancient russian chronicles, pointed out that most of them, from the thirteenth century onward, display churches with onion domes rather than helmet domes. nikolay voronin,the foremost authority on pre-mongol russian architecture, seconded his opinion that onion domes existed in russia as early as the thirteenth century, although they presumably could not be widespread. these findings demonstrated that russian onion domes could not be imported from the orient, where onion domes did not replace spherical domes until the fifteenth century.