Jean Denis Lanjuinais, count, a French statesman, born in Rennes, March 12, 1753, died in Paris, Jan. 13, 1827. When scarcely 22 years of age he won by public competition the professorship of ecclesiastical law in his native city. He acquired reputation as a lecturer and a barrister, was in 1789 elected a deputy to the states general, took an active part in nearly all the great measures of the constituent assembly, framed the bill for the civil constitution of the French clergy, and was the first mover of a plan afterward adopted and embodied in the civil code, by which the registration of births, marriages, and deaths was to be transferred from ecclesiastics to municipal officers. In 1792, being sent to the convention, he resisted the extreme measures of the revolutionists, and opposed the proceedings against Louis XVI., and, being obliged to participate in the trial, voted for his confinement and subsequent banishment. He sided with the Girondists, and was arrested on June 2, 1793, but escaped to Rennes. He resumed his seat as a deputy in 1795, and became president of the convention. On the organization of the directory he was elected to the council of the ancients by 73 departments.
After the 18th Brumaire he was appointed a member of the senate, opposed the consulate for life and the establishment of the empire, received nevertheless the title of count from Napoleon, and was one of the members who voted for the deposition of the emperor in 1814. He was made a peer by Louis XVIII., submitted to Napoleon when he returned from Elba, presided over the chamber of deputies during the hundred days, and on the second restoration resumed his seat in the chamber of peers. Here he advocated liberal opinions, opposing the reactionary measures of the Villele ministry and the growing influence of the clergy. He was acquainted with the oriental languages, entered the academy of inscriptions in 1808, became afterward a member of the Asiatic society of Paris, and was elected associate of the philosophical society of Philadelphia. His works have been published in 4 vols. 8vo (Paris, 1832).