He was the son of George Probert, who married Magdalen, daughter of Charles Williams (of Llangibby).
He was therefore nephew of Sir Trevor Williams; and shared his extreme Protestant views.
[1] Probert was an associate of John Arnold of Monmouthshire in his campaign against local Catholics and the Jesuits.
[3] At the beginning of this period Probert and Arnold were pressing the local justices to take action against practising Catholics.
[1] When Arnold was elected as Member of Parliament for Monmouth Boroughs in 1695, in the Whig interest, it was on the understanding with supporters that he would make way for Probert.