Rene Descartes' Siblings

Descartes was baptised on April 3 or the 4th day of his life.

He was held at the font by his maternal uncle René Brochard, Sieur des Fontaines, magistrate-judge at Poitiers, together with Michel Ferrand, lieutenant general at Châtellerault.

But he had only one godmother: Madame Sain, a relative of his house, whose name was Jeanne Proust, the wife of the royal tax controller at Châtellerault.

He always regarded the grace of this regeneration with inviolable respect; and after his death, they found in his possession his baptismal certificate, which he had carefully preserved and carried with him even to Sweden, as proof of his Christianity. From this extract it is known that the ceremony of his baptism took place in the parish church of Saint George de La Haye, by the ministry of the parish priest named Grisont.

He was named René by his first godfather, and it was decided in the family that he would bear the surname Du Perron, which was a small estate belonging to his relatives, situated in Poitou. This was not a vain title for him: the land of Du Perron was later given to him as his share when he was old enough to own it. He retained this name until the end of his life, despite selling the estate a few years after having received it.

But it appears this surname was only used within his family, to distinguish him from his elder brother. It was scarcely ever used to identify him outside his kin or at college. He resumed the surname Descartes when he left his father’s house; and foreigners among whom he lived soon turned it into Cartesius. This manner of Latinizing names—by dropping the article found in vernacular languages and by adopting a Latinate ending—was common among scholars, so that no one was surprised. Perhaps he was the only one to take issue with it, believing it a child’s duty not to let his name, so carefully preserved by his ancestors, be altered or corrupted.

According to him, Cartesius was a fictitious name, more likely to conceal him from acquaintances and estrange him from his relatives than to preserve him for posterity. And indeed, events showed he had reason to fear this liberty of Latinization, for some of his enemies, wishing to insult him, called him Cartaceus Philosophus. Yet he had to yield to the force of usage, which prevailed over his reasoning. Later he himself acknowledged that Cartesius has a certain sweetness in Latin writings that Descartes lacks. This judgment has been confirmed by his followers, who even in French call themselves Cartésiens more willingly than Descartistes, despite the attempt made by Messieurs Rohault and Clerselier to establish the latter term. Moreover, Descartes’s reason for rejecting the Latin name Cartesius appears all the stronger once one learns that the ancient spelling of the family name was Des Quartes, and in fourteenth-century Latin documents, De Quartis.

Madame Descartes’s delivery, though fortunate for the child, was followed by an illness from which she did not recover. She had been afflicted during her pregnancy with a lung ailment, caused by certain troubles not explained to us. Her son, who reports this fact, merely tells us that she died a few days after his birth.

The father’s care may well have shielded the child from the dangers one might fear in the absence of maternal support; but it could not save him from the infirmities that came with the weak health he brought into the world. He inherited from his mother a dry cough and a pale complexion, which he retained until more than twenty years of age. All the physicians who saw him before then predicted an early death. Yet amid these first misfortunes he received an advantage he remembered all his life: he was entrusted to a nurse who fulfilled her duties with unfailing devotion. He showed her all the gratitude imaginable: never was a foster child more generous, for he ensured her subsistence with a life pension from his estate, faithfully paid until her death.

His father had arranged his various residences in such a way that the six months free from official duties were spent in Poitiers, where he enjoyed retiring near his father-in-law, especially in the first years of his marriage.

Nevertheless, he did not bind himself so strictly to this habit that he did not also seek the pleasures of the countryside—sometimes at his estate of Du Perron, sometimes at La Haye in Touraine, whose lordship was then divided between the houses of Sainte-Maure and Descartes. But the death of his wife greatly contributed to detaching him from his ties to Poitou and his affection for Touraine. It led him to seek new establishments, which he secured some time later in Brittany, where he fixed the rest of his life through a second marriage.

The woman he married in these second nuptials was Anne Morin, daughter of the First President of the Chamber of Accounts of the province. By her he had two more children, a son and a daughter, who reached maturity and helped continue the family line. The son, the elder, bore his father’s name. He was Seigneur de Chavagnes, in the parish of Sucé in the diocese of Nantes, and a counselor in the Parliament of Brittany, like the eldest son from the first marriage.

He had several children with Marguerite du Pont, daughter of Monsieur du Pont, President of the Chamber of Accounts of Brittany. The eldest of these was Messire Joachim Descartes de Chavagnes, still living, who married Mademoiselle Prudence Sanguin, daughter of Monsieur Sanguin, treasurer of the States of Brittany. From this union came three daughters—Prudence, Céleste, and Susanne—married advantageously into the best houses of Brittany: Prudence and Susanne into that of Rosnevinen, and Céleste into that of La Moussaye.

After losing his wife in 1677, and seeing his family so well established, Monsieur de Chavagnes found no obstacle to fulfilling his desire to embrace the ecclesiastical state. He entered through all degrees of ordination to the priesthood, and today exercises his office as clerical counselor in Parliament with great dignity and approval.

He has several brothers, among them Messire François Descartes, who married Dame de Laleu, by whom he had a son and a daughter; and Reverend Father Philippe Descartes, Jesuit, who took his vows in September 1656. This Father, retired at Rennes, is regarded in the Society as a man of great merit in both intellect and piety. He taught mathematics with much esteem and was judged capable of the highest offices in his Order, but always excused himself, and his weak health obtained for him what his modesty alone would not have.

The daughter born to our philosopher’s father in this second marriage was named Anne, like her mother. She married Messire Louis d’Avaugour, knight, Seigneur du Bois de Cargrois (or Kergrais), an estate in the parish of Carquefou in the diocese of Nantes. He was brother to Monsieur d’Avaugour, long employed in embassies and other negotiations for the king in Sweden, Poland, and Germany, who died at Lübeck on September 6, 1657.