"the head of his fair wife which had had eight weary months of imprisoned widowhood and misery, to turn it grey"

On 13 August 1792, the royal family was imprisoned in the tower of the Temple in Marais, under horrible conditions.  Louis was executed on 21 January 1793, at the age of 38.  Marie Antoinette was thereafter referred to as the "Widow Capet."  She went into deep mourning, refusing to eat, and her health rapidly deteriorated.  She suffered from tuberculosis and possibly uterine cancer, which caused her to hemorrhage frequently.  On 3 July, her eight-year-old son Louis Charles was separated from her.  On 1 August, she was removed from the tower and imprisoned at the Conciergerieas Prisoner No. 280.  She was subjected to a show-trial by the Revolutionary Tribunal on 14 October, and accused of orchestrating orgies in Versailles, sending millions of livres of treasury money to Austria, plotting to kill the Duke of Orléans, incest with her son, declaring her son to be the new king of France, and orchestrating the massacre of the Swiss Guards in 1792. She was declared guilty of treason 2 days later, driven through Paris in an open cart, and executed at the Place de la Révolution

The night before her execution, her hair turned white.  This sudden whitening of the hair has since been termed Marie Antoinette Syndrome.  The syndrome involves the loss of all pigmented hairs, leaving only the white hair behind (so there is some balding involved too).  Known triggers include sorrow and fear, fits of rage, shocking news and, bizarrely, overindulgence in sexual activities.