When did Gottfried Wilhelm Leibniz develop differential and integral calculus?

Gottfried Wilhelm Leibniz developed his calculus during the 1670s, following his introduction to the theory of curves by Christiaan Huygens in 1672.1

After years of studying mathematics and experimenting with logic and notation, Leibniz arrived at an algorithm based on the symbols $d$ and $\int$ by the late 1670s. He first published his research on differential calculus in 1684 in the Acta Eruditorum, and he published his work on integration two years later in 1686.12