Michel-Louis Guérard des Lauriers

Michel-Louis Guérard des Lauriers (25 October 1898 – 27 February 1988) was a French Dominican theologian and, later in life, a Traditionalist Catholic bishop who supported sedevacantism and sedeprivationism and was excommunicated by the Holy See.

Biography
Michel-Louis Guérard des Lauriers was born near Paris, France, on 25 October 1898.

In 1921, he entered the Scuola Normale Superiore. He studied for two years in Rome, with Professor Tullio Levi-Civita.

In 1925, he entered the Order of Preachers. He entered the Dominican novitiate of Amiens in 1927. He made his profession in 1930.

He was a normalien and agrégé in mathematics.

Priesthood
On 29 July 1931, des Lauriers was ordained a priest.

In 1933, he became a professor of philosophy at the Dominican school of theology Le Saulchoir, in Belgium. In 1940, he received a doctorate in mathematics with thesis Sur les systèmes différentiels du second ordre qui admettent un groupe continu fini de transformations.

Under Pope Pius XII, he served as a professor at the Pontifical Lateran University in Rome.

In 1979, worried about Archbishop Marcel Lefebvre and a possible deal with the Vatican among other things, des Lauriers wrote to Lefebvre warning him.

Sedeprivationism
Des Lauriers supported the belief that the current state of the papacy, based on Paul VI allegedly teaching heresy in the context of the Magisterium, was that Paul VI could not be a true pope, being only pope materially and not formally. This position known as the Thesis of Cassiciacum.

Episcopacy
On 7 May 1981, after long consideration, des Lauriers was consecrated a bishop by the sedevacantist bishop Thuc in Toulon, France. He was thus excommunicated from the Catholic Church in March 1983 by Cardinal Joseph Ratzinger.

Des Lauriers consecrated two bishops: Günther Storck (a German) on 30 April 1984, and Robert McKenna (an American) on 22 August 1986.

Death and legacy
Des Lauriers died in Cosne-sur-Loire, France, on 27 February 1988, at the age of 89. He is buried in Raveau, France.

There are some bishops who adhere to his Thesis of Cassiciacum: Bishop Geert Stuyver (a Belgian) of the Istituto Mater Boni Consilii (IMBC), and Bishop Donald Sanborn of the Roman Catholic Institute (RCI).

By des Lauriers

 * Le Saint-Esprit, âme de l'Eglise, Étiolles, Seine et Oise : Monastère de la Croix, 1948.
 * Garabandal, S.l., 1965.
 * Lettera ad un religioso di Simone Weil ; trad. di Mariella Bettarini. Risposta alla Lettera ad un religioso di Guérard des Lauriers ; trad. di Carmen Montesano (Lettre à un religieux), Torino : Borla, 1970.
 * La Mathématique, les mathématiques, la mathématique moderne, Paris : Doin, 1972.
 * Homélie (prononcée le 15 mai 1971 pour l'anniversaire de la mort de l'amiral de Penfentenyo de Kervéréguin), Versailles : R.O.C., 1973.
 * La Charité de la vérité, Villegenon : Sainte Jeanne d'Arc, 1985.
 * La Présence réelle du Verbe incarné dans les espèces consacrées, Villegenon : Sainte Jeanne d'Arc, 1987.