Clement's maiden name was Giggs. She was born in 1508 and was the daughter of a gentleman of Norfolk. Sir Thomas More was her legal guardian, bringing her up from a child with his own daughters.
Algebra was probably her special study and More had an "algorisme stone" of hers with him in the Tower of London during his imprisonment, which he sent back to her the day before his execution in 1535. In devotion to her Catholic faith and to its adherents, she risked her life to aid the Carthusian Martyrs, monks starved to death in prison for refusal to renounce the Faith. She obtained also the shirt in which Thomas More suffered, and preserved it as a relic. Sir Thomas Elyot had conveyed to her and her husband the indignation felt by Emperor Charles V, Catherine of Aragon's nephew, at More's resignation, but William Roper, writing years later, had the emperor talking about More's execution; as R. W. Chambers points out, Elyot was not ambassador to the imperial court when More died.
She remained a Roman Catholic, and died in exile at Mechelen in the Habsburg Netherlands on 6 July 1570. She had one child, a daughter, Winifred, who married William Rastell, a judge and More's nephew.
Clement received a humanist education from More despite the gender restrictions and roles. She excelled in math and medicine, yet was also educated in liberal studies such as theology and philosophy. She also had an outstanding command of Greek, as noted by Spanish scholar Juan Luis Vives.
Dictionary of National Biography. London: Smith, Elder & Co. 1885-1900..
Raymond Wilson Chambers (1935), Thomas More, London: Cape.