Stephen Báthory
Multiple members of the Bathory family of Hungary were named Stephen (Báthory István).The first Stephen Báthory (1477-1534) was a Hungarian noble and loyal adherent of King John Zápolya of Hungary. Thus in 1529 he was made governor of Transylvania.
His youngest son Stephen Báthory (1533-1586) was king of Poland from 1575-86. He was succeeded as prince of Transylvania by his brother, Christopher Bathory (1530-81).
Stephen was elected to become king of Poland, after Henry III of Valois returned suddenly to France. He married Anna, daughter of Sigismund II Jagiello.
Stephen Bathory, upon becoming king of Poland, attacked and tried to take Danzig by military force. Danzig successfully defended against him and Bathory had to accept Danzig's continued status as independent city state. He verified this in 1577.
Bathory led the Polish army in a brilliant decisive campaign against the Baltic invaders of Ivan " the terrible" Vasleivich. The russians had invaded Livonia and took Dorpat from the Teutonic knights vassal, the Teutonic Brothers of the sword. The Poles under Bathory routed an Russian force at Vilnius and kept pushing the Russians back to their steppes and their forests. The Polish army took back Smolensk and Pleskov. The Russians abandonned Livonia soon after.
Stephen Bathory planned a Christian alliance against the Ottomans. He also tried to make Russia a vassal state of Poland. He considered this a necessary step for his anti-Ottoman crusade.
When Stephen Bathory died, there was a one year interregnum, which ended with the appointment of a Jew, Saul Wahl, as king of Poland. His reign lasted a single day and he was succeeded by Sigismund III Vasa of Sweden.
The other son of the first Stephen Báthory was also called Stephen Báthory. He was prince of Transylvania from 1571-75. He had succeeded John II Zapolya as prince of Transylvania.
