Cardano's Formula/Historical Note

Historical Note on Cardano's Formula
Cardano's Formula (in an incomplete form) was first published by in $1545$, in his. He learned the technique from, who had sworn him to secrecy. However, as learned in $1543$, the technique had in fact first been discovered by, so he no longer felt bound by his oath to. The latter did not see the matter in the same light, and entered into a feud with that lasted a decade.

The method detailed here is that given by, who delivered it some time around $1650$.

This method was not actually analyzed in depth until the work of, who was the first one to solve the problem of what to do about the "imaginary numbers" that inevitably arose when using this formula.