Complex sentence: On May 29th, 1845, he married Mary Wellesley McTavish, daughter of John McTavish, British Consul at Baltimore, and his wife, Emily from the house of her aunt, the Marchioness Wellesley.
Split into simpler sentences: On May 29th, 1845, he married Mary Wellesley McTavish, daughter of John McTavish, British Consul at Baltimore, and his wife, Emily. The couple wed from the house of her aunt, the Marchioness Wellesley.