Barbara Radziwiłł, queen of Poland (died 1551)

Barbara Radziwiłł was Queen of Poland and Grand Duchess of Lithuania as the second wife of Sigismund II Augustus, the last male monarch of the Jagiellon dynasty. Barbara, a great beauty and already widowed, became a royal mistress most likely in 1543 and they married in secret in July or August 1547. The marriage caused a scandal; it was vehemently opposed by Polish nobles, including Queen mother Bona Sforza. Sigismund Augustus, assisted by Barbara's cousin Mikołaj Radziwiłł the Black and brother Mikołaj Radziwiłł the Red, worked tirelessly to gain recognition of their marriage and to crown Barbara as Queen of Poland. They succeeded and Barbara's coronation was held on 7 December 1550 at Wawel Cathedral. However, her health was already failing and she died just five months later. Even though it was brief, her reign propelled the Radziwiłł family to new heights of political power and influence.