Biographical Summary #1:

"...Margaret Pierce [widow of Morris Whitesides] married in 1845 to Brigham Young leader of the Mormons, and sealed to him January 22, 1846, and she bore him one child, a son named Brigham Morris Young, born January 18, 1854.

Margaret was sister of Mary Harvey (Pierce) Young, another wife of Brigham..."

Margaret and Mary's parents were Robert and Hannah (Harvey) Pierce....

SOURCE: Find A Grave Memorial# 50029907. www.findagrave.com

Biographical Summary #2:

Brigham Young and Margaret Pierce were married on 16 Jan 1845 in Nauvoo, Hancock, Illinois.T Margaret Pierce (daughter of Robert Pierce and Hannah Harvey). She was born on 19 Apr 1823 in Ashton, Delaware, Pennsylvania.She died on 16 Jan 1907 in Salt Lake City, Salt Lake, Utah. She was described as little above medium height, fair complexion.

SOURCE: Unknown

Marriage:

MARGARET first married Morris Whitsides, who died after seven months of marriage. She then married Brighham Young at age 21 on 16 January, 1945.They had one child, Brigham Morris Young.

SOURCE: Unknown

Additional Resources:

1. "AUTOBIOGRAPHY OF MARGARETTE P.W. YOUNG," HOLOGRAPH, CHURCH HISTORICAL DEPARTMENT.
2. HORNE, ALICE MERRILL, "ONE OF THE PIONEERS," YOUNG WOMEN'S JOURNAL 15 (APRIL 1904):162-166.
3. "WIDOW OF PRESIDENT BRIGHAM YOUNG WHO DIED LAST NIGHT...," DESERET EVENING NEWS. 17 (JANUARY 1907):10.