Chess began in India during the time of gaonim (or perhaps a bit earlier). It was based on warfare which is most more intricate. The only major changes in rules were at the end of the Middle Ages (period of the last rishonim, early achronim) when the vizier became the queen and become a powerful peace (the bishops also got more powerful, and stalemates became draws instead of an inferior form of checkmate, and tghe game became much shorter). The elephant becoming a bishop didn’t involve a rule change (it came from Europeans not knowing what an elephant looked like, and do a lousy job of pronouncing the Arabic name).
The older version is the one discussed in Ibn Ezra’s treatise. For those who can’t figure out, there is always checkers. For those who chess to be too easy, there is always gemara.