Complex sentence: Esther Gottlieb, his widow, was the founder and president of the Foundation who set it up at the bequest of her husband in 1976 according to provisions in her husband's will with assets of some $6 million derived from the sale of his works.
Split into simpler sentences: Esther Gottlieb, his widow, was the founder and president of the Foundation. She set it up at the bequest of her husband in 1976 according to provisions in her husband's will with assets of some $6 million derived from the sale of his works.