Complex sentence: Meredith's wife Amy, daughter of Charles Percy of Weredale Park, Montreal, by his wife Annie (one of his mother's first cousins), the daughter of (Ralph) Henry Howard Meredith (1815-1892) of Port Hope, Upper Canada.
Split into simpler sentences: Meredith's wife Amy was the daughter of Charles Percy of Weredale Park, Montreal. Amy's mother Annie (one of his mother's first cousins) was the daughter of (Ralph) Henry Howard Meredith (1815-1892) of Port Hope, Upper Canada.