Elena Glinskaya ruled what would become Russia as regent for her son, wisely and ably in fact, until her life and reign were brought to brutal ends.
Amalasuntha ruled Rome after the Roman Empire's fall. She is known for being a wise leader of the Ostrogoths, first as regent, then as the ruling monarch.
Alice Perrers was quite the ambitious mistress, though we have to have some sympathy for her—she has been hated in her time and ever since.
Anne Hyde nearly became Queen of England but died before her chance to. She was a commoner who, through good luck, became the mother of Queens Mary II and Anne.
Sarah Lyttleton was a beloved mother figure to Queen Victoria's nine children, all of whom kept fond memories of her as they lived their grand futures.
When Anne Boleyn was executed, her husband famously moved on eleven days later. But her mother’s devastation often goes unnoticed.
Blanche of Castile served as regent of France on two occasions and held great power in the country even when she wasn’t ruling.
Elizabeth Tailboys was a daughter of Henry VIII, but since she was illegitimate, her story isn't told much, though it seems quite fascinating.
Augusta Victoria of Schleswig-Holstein was a minor princess distantly related to Queen Victoria, and married a distant relative, the last Kaiser of Germany.
Augusta of Saxe-Weimar-Einsach was just another German princess who became Queen of Prussia. But after the unification of Germany, she became an Empress.