Apollonius (247-222 B.C.)

    Appolonius was a Greek geometer. His role in early Calculus concerning the tangent line was remarkable. He gave one of the earliest definitions of a tangent line. Apollonius described a tangent line to a conic as a line such that "no other straight line can fall between it and the conic section.”His treatise about conics was the most important work on conic sections (ellipses, hyperbolas, and parabolas) up to the 17th century.