Shulchan Aruch
The "Acharonim" follow the "Rishonim", the "first ones"—the rabbinic scholars between the 11th and the 16th century following the "Geonim" and preceding the "Shulchan Aruch". The publication of the "Shulchan Aruch" thus marks the transition from the era of Rishonim to that of Acharonim.