Birthday Party for Rudolf Leopold

One of the world's most prominent art collectors, Rudolf Leopold, died last month in Vienna, Austria.

Known for his encompassing passion for German Expressionism, he amassed a huge display of works by Egon Schiele.

Eventually, he donated the bulk of his collection to the government which created a museum to house it.

Today's AK Files takes a closer look at his collection and the dogged -- often controversial -- perseverance he possessed to assemble it.