Complex sentence: Agostino Loverdo is placed by Capone as head of the "Union Siciliane", however the organizations value greatly declines over the decade, quietly dissolving by the late 1930s.
Split into simpler sentences: Agostino Loverdo is placed by Capone as head of the Union Siciliane. However, the organization's value greatly declines over the decade, quietly dissolving by the late 1930s.