How did the ideal Gas Law originate?
The simplest complete form is the combined law form, or Ideal Gas Law.
It was derived by combining the relationships of each of the other general laws (Boyles Law (1627-1691), Charles' Law (1746-1823), Guy-Lussacs Law (1778-1850). The related Dalton’s Law (1766-1844) describes partial pressures.
The other primary one to remember is the relationship to moles: PV = nRT (Avogadro’s Law (1776-1856)). Here you need to be careful to use the correct “gas constant”, R, which has different values for different dimensions.