Original: During the January Uprising in 1863 heavy city fights occurred, but were brutally pacified by Mikhail Muravyov, nicknamed The Hanger by the population because of the number of executions he organized.
Simplified: During the January Uprising in 1863 heavy fighting occurred within the city, but was brutally pacified by Mikhail Muravyov, by the population because of the number of executions he organized.