What language was Diablo written in?

I really love Diablo (the first one, the second ruined the franchise but getting rid of the atmosphere and making it about collecting items as currency) and want to know what language it was written in. Also, I'm currently playing on US East if anyone wants to play with me.

I really wish Blizzard would fix the fucking hacking though. It should take them a single engineer to do it at this point.

If you like it so much use a disassembler and reconstruct the the game.
Its not that big, and you can check out all the hacks they used so that Diablo would run at full speed in the 90's.
Using Sepples for game engines is always done at the architecture-level(using the full "OOP abstraction power" of Sepples would make games unplayable), the real code is low-level C and possibly Asm. Newer games abuse more of Sepples, so they take gigabytes of ram and set the latest cards to frying temps. Back when ram was a limited resource, the key parts were precomputed, swapped, generated and transformed with clever hacks, unlike the Java-level code made for modern games.