Where does the equal sign, "=", used in mathematics originate from?

Question

What branch of mathematics was founded from a paper "On a Characteristic Property of All Real Algebraic Numbers" (1874) by Georg Cantor, who built on the work of Zeno, Bernard Bolzano & Richard Dedekind, which, in turn was followed up by Bertrand Russell, Ernst Zermelo, Abraham Fraenkel & Henri Lebesgue?

Answer 1

16th century England
The sign was first recorded by Anglo-Welsh physician and mathematician Robert Recorde in his mathematics textbook "The Whetstone of Witte" (1557).