Excerpts from Books and Wikipedia
"Rudolf I (1 May 1218 – 15 July 1291) was the first king of Germany from the House of Habsburg. The first of the count-kings of Germany, he reigned from 1273 until his death. Rudolf's election marked the end of the Great Interregnum which had begun after the death of the Hohenstaufen Emperor Frederick II in 1250. Originally a Swabian count, he was the first Habsburg to acquire the duchies of Austria and Styria in opposition to his mighty rival, the Premyslid king Ottokar II of Bohemia, whom he defeated in the 1278 Battle on the Marchfeld. The territories remained under Habsburg rule for more than 600 years, forming the core of the Habsburg Monarchy and the present-day country of Austria." [Wikipedia]