Princess Olga of Kiev

Olga’s husband ruled Kieven Rus, a fairly large part of Eastern and North Eastern Europe. The Drevlians, a small city state of the empire, rose up in protest and killed her husband. Since Olga’s son was only three years old, she took the power of her kingdom into her hands with the support of Russian army. To mend ties and avoid civil war, the Drevilians proposed to marry their prince to Olga. When the matchmaking ambassadors arrived with their marriage proposal, she buried the whole envoy alive.

She then sent back word that she accepted the marriage proposal but wanted to be escorted by a large noble escort as befitting her status. When the Drevlian nobles showed up, she offered them a large bath house to clean up from the long journey. She then burnt it to the ground with everyone in it.

She then invited the Drevlian populace to a funeral for her husband, which was attended by many as it was basically a feast with free food and booze. She then ordered her soldiers to murder over 5,000 unarmed and drunken civilians. Finally, she marched on their city. The Drevlians surrendered and offered to pay a huge tribute to spare their lives. So she granted the request, and asked as a tribute, only for a bird from each house. This was a seemingly kind and reasonable request, that the city happily fulfilled.

You see birds often nested in the roofs of these old houses. She proceeded to order her men to tie sulfur matches to the birds and lit them on fire. This sent the fiery flock back to their nests that burnt the whole city down.