 He reigned only a decade, but is considered one of the most successful kings in Polish history, particularly in the realm of military history.His signal achievement was his victorious campaign in Livonia against Russia in the middle part of his reign, in which he repulsed a Russian invasion of Commonwealth borderlands and secured a highly favorable treaty of peace (the Peace of Jam Zapolski).Stephen Báthory was born on 27 September 1533 in the castle at Somlyó, also known as Szilágysomlyó (today's Șimleu Silvaniei).