Complex sentence: In 1870, Queen Victoria, finding the Imperial State Crown too heavy, designed and commissioned this delightful small crown to be made, using some of the diamonds from her own collection-mainly from a large necklace.
Split into simpler sentences: In 1870, Queen Victoria, finding the Imperial State Crown too heavy, designed and commissioned a small Diamond Crown. This delightful crown was made using some of the diamonds from her own collection-mainly from a large necklace.