Newton's masterpiece was written in "New Latin", and is invariably known by its abbreviated Latin title. The full title, in Latin, is Philosophiæ Naturalis Principia Mathematica.
Classics students will note that the word mathematica is in the nominative case, not the genitive. In other words, the title is not (as the abbreviated Latin name might lead you to believe) "Principles of Mathematics".
Wikipedia notes that 'The Principia is considered one of the most important works in the history of science. The French mathematical physicist Alexis Clairaut assessed it in 1747: "The famous book of Mathematical Principles of Natural Philosophy marked the epoch of a great revolution in physics. The method followed by its illustrious author Sir Newton ... spread the light of mathematics on a science which up to then had remained in the darkness of conjectures and hypotheses.'
That'll be why it's called Mathematical Principles of Natural Philosophy!
(We'll overlook the unconventional reference to "Sir Newton").
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