Complex sentence: Queen Hedwig Eleonora was a very strong willed and dominating woman, whose temper was feared in the Royal castles, and she entirely dominated the Swedish Court until her death, as one of the most notable of the queens of Sweden.
Split into simpler sentences: Queen Hedwig Eleonora was a very strong willed and domineering woman, whose temper was feared in the royal castles. She entirely dominated the Swedish court until her death as one of the most notable of the queens of Sweden.