The Arti dei Fornai was one of the Arti Minori ("lesser trades") of the Guilds of Florence, founded prior to 1236. It was composed of bakers, "pistori" (people who created bread for houses), and, as of 1429, millers. Although it once had a decent position of seventh among the fourteen minor guilds, it dropped to ninth out of ninth after the middle guilds separated.
References
Arti dei Fornai Wikipedia(Text) CC BY-SA