Complex sentence: Ingres'portrait of Louis-François Bertin was a critical and popular success, but the sitter was a naturally private person and although his family worried about caricature and disproved, it became widely known and sealed the artist's reputation.
Split into simpler sentences: Ingres'portrait of Louis-François Bertin was a critical and popular success, but the sitter was a naturally private person. Although his family worried about caricature and disproved, it became widely known and sealed the artist's reputation.