The Young and McAllister families were prominent families in the Associate Presbyterian community in Philadelphia.

William Young (1755-1829) was a Philadelphia bookseller and later a manufacturer at Rockland, Delaware. He was born near Irvine, Scotland, June 27, 1755, to John Young (1730-unknown) and Agnes Wallace Young (1729-1761). He entered the Associate Presbyterian seminary in Scotland and while still a student in about 1779, married Agnes McLaws (1754-1793), the daughter of an Associate Presbyterian family. Young never completed his studies at the seminary, opting instead to try his hand in a career as a book dealer. At the age of twenty-eight, he left Scotland with his wife and son for America, and never returned. The family arrived at Philadelphia in June 1784.

In Philadelphia, Young continued in the business that he knew best, the book trade. Opening a bookshop and printing establishment at his home on the corner of Second and Chestnut Streets, Young prospered. While his business prospered, Young suffered personal loss, including his wife during the great yellow fever epidemic of 1793.

In 1802, Young sold his printing business to William W. Woodward (1769-1837), married Rachel Anderson (1770-1836), a woman fifteen years his junior, and moved his family to a newly built mansion in Rockland, Delaware. In Rockland, he started a paper manufactory, which provided much of the stock used by Woodward in the Philadelphia printing shop. In 1804, Young was awarded a gold medal for developing a new paper. In 1814, the paper mill burned and was reopened as a woolen mill, but Young overextended his financial resources. The woolen mill soon swallowed most of his ready cash, expansion became impossible. Over the years, Young had received large credits and loans from the firm of John McAllister & Son (the son being his own son-in-law), and upon Young's death in 1829 his estate was found to owe the McAllisters over $57,000. With the woolen mill proving unsuccessful, the Youngs returned to Philadelphia in 1816. It was here that Young died on May 12, 1829.

John McAllister Jr. (1786-1877) ran the Philadelphia optical firm of that same name. He was born on June 19, 1786, the son of John McAllister (1753-1830) and Frances (Wardale Lieber) McAllister (1746-1814). In Philadelphia, John McAllister Sr. began a manufactory of whips and canes, and in 1799 purchased an eyeglass business, which he added to his other products. In 1800, he opened a retail shop for these goods in partnership with James Matthews at 50 Chestnut Street. The McAllisters lived next door at No. 48, a three-story brick house that John Sr. built in 1794.

McAllister began his formal education at the age of four. He enjoyed music and painting, but after a very brief foray into dance, declined to pursue the study further. Only ten when he entered the University of Pennsylvania in 1796, McAllister graduated just before his seventeenth birthday in 1803, and at the time of his death, three-quarters of a century later, he had become the University's oldest living alumnus. Following graduation, McAllister entered the "counting house" of Montgomery & Newbold, where he acquired a general knowledge of business and international trade. He left the firm in 1807 and went into business with his father. McAllister Jr. took complete charge of the Chestnut Street retail outlet and his father devoted himself to the manufacturing end of the enterprise.

In 1811, John McAllister Jr. married Eliza Melville Young (1790-1853), a childhood friend who had grown up in the same church, the daughter of his father's intimate friend, William Young. Over the next twenty years, the McAllister's had ten children.

The firm of McAllister & Son prospered, eventually centering its production on optical and scientific instruments. McAllister operated his business alone for five years after his father’s death and in 1835 turned it over to his eldest son, William Young McAllister (1812-1896), and retired to the life of a leisured gentleman, though not yet fifty years old. Widowed in 1853 when nearing seventy, John McAllister Jr. survived another quarter century. On his death, December 17, 1877, he left five children, fourteen grandchildren, and several great-grandchildren.