 His first major opponent was his brother Albert VI, who challenged his rule.He did not manage to win a single conflict on the battlefield against him, and thus resorted to more subtle means.He held his second cousin once removed Ladislaus the Posthumous, the ruler of the Archduchy of Austria, Hungary and Bohemia, (born in 1440) as a prisoner and attempted to extend his guardianship over him in perpetuity to maintain his control over Lower Austria.