The general governed the country with an iron hand.
Origin
1840-50
Examples from the web for iron hand
Then he wet a comb at the cabin's iron hand pump and slicked back his hair and his little brother's hair.
Only the iron hand rails remain from the lower run of stairs.
Talk not to us of weakness when you have so long broken our spirits by the iron hand of oppression.
British Dictionary definitions for iron hand
iron hand
noun
1.
harsh or rigorous control; overbearing or autocratic force: he ruled with an iron hand
Idioms and Phrases with iron hand
iron hand
Rigorous control, as in He ruled the company with an iron hand. This usage is sometimes put as iron hand in a velvet glove, meaning “firm but seemingly gentle control,” as in She runs the town with an iron hand in a velvet glove. [ c. 1700 ]