William Cathcart was born in the County of Londonderry, in the north of Ireland, Nov. 8, 1826; his parents, James Cathcart and Elizabeth Cously, were of Scotch origin, the stock known as Scotch-Irish in the United States. He was brought up in the Presbyterian Church, of which, for some years, he was a member. The Saviour called him into his kingdom in early life, and taught him that he should preach the gospel. He was baptized by Rev. R. H. Carson, of Tubbermore, in January, 1846. He studied Latin and Greek in a classical school near the residence of his father. He received his literary and theological education in the University of Glasgow, Scotland, and in Horton, now Rawdon College, Yorkshire, England. He was ordained pastor of the Baptist church of Barnsley, near Sheffield, England, early in 1850. From political and anti-state church considerations he determined to come to the United States in 1853, and on the 18th of November in that year he arrived in New York. In the latter part of the following month he became pastor of the Third Baptist church of Groton, in Mystic River, Conn. In April 1857, he took charge of the Second Baptist church of Philadelphia, Pa., where he was since labored. In 1873, the University of Lewisburg conferred on Mr. Cathcart the degree of Doctor of Divinity. In 1876, on the retirement of Dr. Malcom from the presidency of the American Baptist Historical Society, Dr. Cathcart was elected president, and has been re-elected at each annunal meeting since. In 1875, in view of the Centennial year of our national independence, the Baptist Ministerial Union, of Pennsylvania, appointed Dr. Cathcart to prepare a paper, to be read at their meeting in Meadville in 1876, on "The Baptists in the Revolution." This paper, by enlargement, became a duodecimo volume, entitle "The Baptists and the American Revolution." Dr. Cathcart has also published a large octavo, called "The Papal System," and "The Baptism of the Ages and of the Nations."
source: Cathcart's Baptist Encyclopedia