Final answer:
The houses were mistakenly burned by William the Conqueror's guards after his coronation on Christmas of 1066.
Step-by-step explanation:
Mistaking cheering for a riot, William the Conqueror's guards burned local houses after his coronation on Christmas of what year? The correct answer is a) 1066. William the Conqueror was crowned King of England on Christmas Day of 1066, following his victory at the Battle of Hastings earlier that same year. This tumultuous time saw the transition of England to Norman rule, which included the construction of many churches and other structures, as well as the rebuilding of those affected by the common occurrence of fires in medieval Europe, similar to the blaze that tragically engulfed the Cathedral of Notre Dame in 2019.