Karl Theodor Wilhelm Weierstrass was born in Osterfelde, Westphalia (Germany) on October 31, 1815. Weierstrass was regarded as the most famous mathematician in 19th-century Germany after Carl Friedrich Gauss and Bernhard Riemann. He received his education at the Catholic Gymnasium in Paderborn, the University of Bonn, and he graduated from the Theological and Philosophical Academy at Münster in 1841.

Karl Weierstrass started his professional career by teaching in Latin schools (Gymnasium). He spent most of this period teaching in Braunsberg until 1855. His university career started in the following year when the Industry Institute (Berlin) appointed him as a professor. In 1857 Karl Weierstrass became professor at the University of Berlin where he remained until his retirement. The University of Koningsberg awarded him a honorary doctorship in 1854 for his mathematical articles, and in 1856 the Berlin Academy elected him as a member.

Weierstrass's major contributions to the field of mathematics were his new elaborations and new applications of the Abelian functions. Since he was the only professor in Germany teaching these courses and new theories, he attracted many students and faculty from all over the country, and his skill in lecturing was later described as "masterly". He became dissatisfied with the circulating transcripts of his lectures and in the way his theories were applied in textbooks. Weierstrass began to publish his courses with the aid of some of his promising students. Seven volumes of his lectures were published; five were published after his death (1897). (Mathematische Werke, 7 vols. Berlin, 1894-1927)

Karl Theodor Wilhelm Weierstrass died in Berlin February 19, 1897.

Thomas Craig was born in Pittston, PA on December 20, 1855. He graduated from Lafayette College (1875) with a degree in civil engineering and received the Ph.D. in mathematics from The Johns Hopkins University in 1879. Craig was a student of Hopkins Professor of Mathematics, James Joseph Sylvester and was later appointed to the faculty. Craig was appointed Professor of Mathematics in 1892, a position he held until his death on May 8, 1900. Thomas Graig published many articles and books, one of them being a book on linear equations.