\begin{definition}[Definition:Congruence (Number Theory)/Historical Note]
The concept of '''congruence modulo an integer''' was first explored by {{AuthorRef|Carl Friedrich Gauss}}.
He originated the notation $a \equiv b \pmod m$ in his work {{BookLink|Disquisitiones Arithmeticae|Carl Friedrich Gauss}}, published in $1801$.
\end{definition}