Complex sentence: Caroline Lake Quiner (1839-1923), mother of Laura Ingalls Wilder, was born in the then Town of Brookfield, currently City of Brookfield, was descended from pioneers who could trace their ancestry to the Mayflower.
Split into simpler sentences: Caroline Lake Quiner (1839-1923), mother of Laura Ingalls Wilder, was born in the then Town of Brookfield, currently City of Brookfield. She was descended from pioneers who could trace their ancestry to the Mayflower.