Complex sentence: Horváth was the oldest son of an Austro-Hungarian diplomat of Hungarian origin from Slavonia, Edmund (Ödön) Josef Horvát, and Maria Lulu Hermine (Prehnal) Horvát, who was from an Austro-Hungarian military family.
Split into simpler sentences: Horváth was the oldest son of the Austro-Hungarian diplomat of Hungarian origin from Slavonia. Dr. Edmund (Ödön) Josef Horvát and Maria Lulu Hermine (Prehnal) Horvát, who was from an Austro-Hungarian military family.