Complex sentence: In 1547 the coronation of the first Russian Tsar, Ivan the Terrible, took place in this cathedral, while from 1721 it was the scene of the coronation of the Russian emperors.
Split into simpler sentences: In 1547 the coronation of the first Russian Tsar, Ivan the Terrible, took place in this cathedral. From 1721 it was the scene of the coronation of the Russian emperors.