Births on October 18

Anna Jagiellon, daughter of Sigismund I of Poland (d. 1596)

Anna Jagiellon (Polish: Anna Jagiellonka, Lithuanian: Ona Jogailaitė; 18 October 1523 – 9 September 1596) was Queen of Poland and Grand Duchess of Lithuania from 1575 to 1587.

Daughter of Polish King Sigismund I the Old and Italian duchess Bona Sforza, Anna received multiple proposals, but remained unmarried until the age of 52. After the death of King Sigismund II Augustus, her brother and the last male member of the Jagiellonian dynasty, her hand was sought by pretenders to the Polish throne to maintain the dynastic tradition. Along with her then-fiancé Stephen Báthory, Anna was elected as co-ruler in the 1576 royal election of the Polish–Lithuanian Commonwealth. Their marriage was a formal arrangement and distant.

While Báthory was preoccupied with the Livonian War, Anna spent her time on local administrative matters and several construction projects, including the city wall Stara Prochownia to protect Sigismund Augustus Bridge. After her husband's death in December 1586, Anna had the opportunity to remain on the throne as the sole ruler, but instead promoted her nephew Sigismund III Vasa, whose reign established the House of Vasa on the Polish throne for the next eighty years (1587–1668).