Question: Did Ivan the Terrible use the Byzantine calendar?, Answer:Yes, Description of Byzantine calendar: The calendar used by the Eastern Orthodox Church from c. 691 to 1728, Fact1: Ivan the Terrible was the Tsar of Russia from 1530 to 1585. , Fact2: The Byzantine calendar was the official calendar of the Russian government from 988 to 1700., Fact3: The Tsar was the leader of the Russian government. 
Step1: What was Ivan the Terrible's role from 1530 to 1585?, Step2: What country was Ivan the Terrible #1 of?, Step3: Was the Byzantine calendar the official calendar of #2 from 1530 to 1585?, Wikipedia page for step 1: Ivan the Terrible , Wikipedia page for step 2: Ivan the Terrible , Wikipedia page for step 3: Byzantine calendar, not_definitive_answer: False, incorrect_answer: False