The marriage of Catherine de' Medici to the future King Henry II of France was arranged by Pope Clement VII, her relative, to bind the wealthy Medici banking family to French royalty. The lavish Marseille wedding, attended by the Pope himself, set in motion decades of Catherine's influence over French politics and culture, including the brutal St. Bartholomew's Day Massacre decades later.
Catherine arrived in France as something of an outsider—Italian, merchant-class by origin despite her family's wealth, and initially overshadowed at court by her husband's mistress, Diane de Poitiers. For years she struggled to produce an heir, facing whispers of infertility and even threats of annulment.
She eventually bore ten children, several of whom became kings of France, and after Henry's death in a jousting accident in 1559, she became one of the most powerful women in Europe as regent and political mastermind for her sons' reigns.
Her legacy is complicated: she's credited with bringing Italian Renaissance culture, cuisine, and ballet to the French court, but she's also remembered for her role in the religious violence that tore France apart, including the massacre of thousands of Huguenots in 1572.