Abel-Ruffini Theorem/Historical Note

Historical Note on Abel-Ruffini Theorem
The Abel-Ruffini Theorem, on the general insolubility of the quintic, was stated by, who built an incomplete proof in $1799$.

provided the first complete proof in $1823$.

He published this in a small pamphlet Mémoire sur les équations algébriques ou on démontre l'impossibilité de la résolution de l'équation générale du cinquième degré ($1824$) at his own expense.

It later transpired that had independently proved the theorem some years earlier, in a work that was not published in $1846$, some $25$ years after his death.