Blizzard will release a remake ofDiablo inside ofDiablo III as part of an upcoming “20th anniversary” patch, the company said today. It’ll include a 16-level dungeon and the four main bosses from the firstDiablo.

The patch,The Darkening of Tristam,will be free toReaper of Souls owners on both PC and console. Says Blizzard in a press release:

Celebrate 20 years of Diablo by traveling back into the depths of the Cathedral where it all began in this upcoming Diablo III: Reaper of Souls content update. Get ready to explore a monster-filled dungeon 16 levels deep, and come face to face with the four main bosses from the original game—all with retro touches like special graphics filters and eight-direction character movement.

The patch will be live on the public test realm next week.