Queen Tamar of Georgia. Ruled the Kingdom of Georgia from 1184-1213.
Even though her father left her the throne, a lot of her counselors were wary about having a woman rule, so they picked out a husband for her - Yuri, Prince of the Rus’ (Russia). She complied, but when he started getting drunk and abusing her, she called off the marriage and kicked him out of Georgia. He came back with an army to try and overthrow her, but she and her armies beat them to a pulp and sent them packing.
A lot of neighboring countries tried to invade, actually, because they thought that a woman leader was a sign of weakness.
She showed them otherwise.
She expanded the Kingdom of Georgia to its largest size, created a Golden Era of peace in which the greatest Georgian poetry and art was created, and eventually married her friend and equal, David Soslan, prince of Alan.
She was incredible, guys.