Lowell Mason had four sons, all active musically. The two eldest, Daniel Gregory and Lowell, formed a publishing company in New York City. Lowell, the third son, Henry, and Emmons Hamlin founded Mason & Hamlin, a firm that first made organs and later made pianos. The youngest son, William Mason, 1829-1908, b. Boston, was a distinguished concert pianist and teacher. He studied in Europe with Liszt and others. With Theodore Thomas he organized a chamber-music ensemble that did much to interest Americans in chamber music. He wrote Memories of a Musical Life (1901).

The son of Henry Mason, Daniel Gregory Mason, 1873-1953, b. Brookline, Mass., was important as a composer, writer, and lecturer. He studied with John K. Paine at Harvard and with D'Indy in Paris. In 1905 he joined the faculty of Columbia, where he was professor of music from 1929 to 1940. His writings include Music in My Time (1938) and The Quartets of Beethoven (1947). Among his compositions are the festival overture Chanticleer (1928); three symphonies, of which the third, known as Lincoln Symphony (1936), is outstanding; and chamber music.

Originally, the boundary between Maryland and Pennsylvania. The 233-mi (375-km) line was surveyed by Charles Mason and Jeremiah Dixon in 1765–68 to define the disputed boundaries between the land grants of the Penns, proprietors of Pennsylvania, and the Baltimores, proprietors of Maryland. The term was first used in congressional debates leading to the Missouri Compromise (1820) to describe the dividing line between the slave states to its south and the free-soil states to its north. It is still used as the figurative dividing line between the North and South.

Learn more about Mason-Dixon Line with a free trial on Britannica.com.

(born Nov. 3, 1798, Fairfax county, Va., U.S.—died April 28, 1871, Alexandria, Va.) U.S. politician. A grandson of George Mason, he practiced law in his native Virginia from 1820. He served in the state legislature (1826, 1828–32), the U.S. House of Representatives (1837–39), and the U.S. Senate (1847–61). An advocate of secession, he resigned his Senate seat in 1861. Appointed Confederate commissioner to England, he was captured at sea with John Slidell aboard the Trent and imprisoned for two months (see Trent Affair). Released in 1862, he remained in England until 1865 but was unable to win support for the Confederate cause.

Learn more about Mason, James Murray with a free trial on Britannica.com.

(born May 15, 1909, Huddersfield, Yorkshire, Eng.—died July 27, 1984, Lausanne, Switz.) British film actor. After studying architecture at the University of Cambridge, he made his screen debut in Late Extra (1935) and soon became a star in British films such as The Man in Grey (1943), The Seventh Veil (1945), and Odd Man Out (1947). He moved to Hollywood in the late 1940s but continued to make films in Britain as well. Noted for his urbane characterizations of flawed individuals, he appeared in more than 100 movies, including Madame Bovary (1949), A Star Is Born (1954), North by Northwest (1959), Lolita (1962), Georgy Girl (1966), The Boys from Brazil (1978), and The Verdict (1982).

Learn more about Mason, James with a free trial on Britannica.com.

Learn more about Mason, George with a free trial on Britannica.com.

(born Feb. 28, 1797, near Buckland, Mass., U.S.—died March 5, 1849, South Hadley) U.S. pioneer in higher education for women. She studied at various academies, supporting herself from age 17 by teaching. Her success as a teacher and administrator, and the demand for the young women she had trained, led to her plan for a permanent instructional institution for women. The school she founded in South Hadley, Mass., opened in 1837 as the Mount Holyoke Female Seminary (the forerunner of Mount Holyoke College), and she served as its principal until her death.

Learn more about Lyon, Mary (Mason) with a free trial on Britannica.com.