Complex sentence: Jewelry containing Yogos was given to First Ladies Florence Harding and Bess Truman and in addition many gems were sold in Europe, though promoters' claims that Yogos are in the crown jewels of England or the engagement ring of Princess Diana are dubious.
Split into simpler sentences: Jewelry containing Yogos was given to First Ladies Florence Harding and Bess Truman and in addition many gems were sold in Europe. However, promoters' claims that Yogos are in the crown jewels of England or the engagement ring of Princess Diana are dubious.