The two names most associated with Saint Basil's Cathedral, Barma and Postnik, may not belong to two separate people at all. Documentary evidence for the building's construction between 1555 and 1561 is thin enough that some architectural historians now argue Barma and Postnik Yakovlev were one man known by two names, rather than a pair of master builders working together, though the traditional two builder account is still the more commonly repeated version.
What the surviving evidence rules out more confidently is the story attached to whichever of them actually built it. Popular legend holds that Ivan the Terrible had the architect blinded once the cathedral was complete, so that he could never design anything to equal it again. Historians treat the story as invention: the same architect is documented working afterward on the Cathedral of the Annunciation in Kazan and on the walls and towers of the Kazan Kremlin, the same commission a blinded man could not have carried out.
The building's most famous feature was also not part of the original design. Written descriptions and a surviving seventeenth century engraving suggest the cathedral's domes were originally simpler and closer to uniform in shape than the swirling, brightly patterned onion domes visible today; historians broadly agree the vivid painted colors and patterns were a later addition, applied well after Ivan's reign, and the underlying helmet shaped domes themselves have been rebuilt more than once following fires. What survives, in other words, is not quite what was built, and not quite what legend says was built either, a cathedral whose most repeated stories about its own construction turn out to be the least reliable part of its history.