Complex sentence: Although she brought him a dowry of only $300, she possessed a frugal mind and a business judgment that he declared better than that of most merchants, and she assisted him in the practical details of his business.
Split into simpler sentences: Although she brought him a dowry of only $300, she possessed a frugal mind and a business judgment that he declared better than that of most merchants. She assisted him in the practical details of his business.