At the age of sixteen Francois II de Roye de La Rochefoucauld, Comte de Roucy et de Roye, went to Rome with his cousins, the Duc de La Roche-Guyon and Monsieur de Liancourt, to forsake officially his protestantism which he forswore at the hands of the Pope. 
Having enrolled in the army, he became an officer of the Royal Regiment; then he became Captain of the Scots Guards and then Commandant of Bapaume. On 8 February 1689 at Versailles, he married Catherine Francoise d'Arpajon and they became the parents of six children. 
In December 1702 the military high command appointed him Lieutenant-General of the Royal armies and, in 1704, he saw action at the siege of Brisack, at Spire and at Rochstaedt. When Marshall d'Harcourt, worn out with illness, wished to give up his position in the Regent's Council in favour of his first cousin, the Comte de Roucy, the Regent, who had never liked d'Harcourt, refused to allow this. 
The Comtesse de Roucy died on 8 December 1716 and the Comte on 29 November 1721 in Paris. 
 

Source: Leo van de Pas