The mother died in 1775.

The Abbé de l'Epée, astounded by the striking similarity between the
facts and Joseph's account of himself, at once came to the conclusion
that Providence had chosen him as the instrument for righting a great
wrong, and set himself to supply the missing links in the chain of
evidence, and to restore his ward to what he doubted not was his
rightful inheritance. He maintained that young Solar's mother, either
wearied with the care of a child who was deprived of speech and
hearing, or to secure his estates for herself or her daughter, had
given her son to Cazeaux to be exposed, and that that ruffian had made
tolerably certain of his work, by carrying the lad 600 miles from
home, to the vicinity of Peronne, and there abandoning him in a dense
wood, from which the chances were he would never be able to extricate
himself, but in the mazes of which he would wander till he died. God
alone, the Abbé declared, guided the helpless and hungry lad within
the reach of human assistance, and sent the traveller to rescue him,
opened the woman's heart to give him shelter, and brought him to
Paris, so that he might be instructed and enabled to tell his doleful
tale.

Fired by enthusiasm, the Abbé succeeded in engaging the co-operation
of persons of the highest eminence. The Duc de Penthièvre, a prince of
the blood, espoused the cause of the wronged noble, and provided for
his support as became his supposed rank. From the same princely
source, also, funds were forthcoming to obtain legal redress for his
hardships, and to prosecute his claims before the courts. Proceedings
were instituted against Cazeaux, who was still alive, and a formal
demand was made for the reinstatement of the foundling of Peronne in
the hereditary honours of Solar. The boy was taken to Clermont, his