Rabbi Isaac of Dueren רבי יצחק בן מאיר מדורא
his book was the code of kashrut for Ashkenaz until the Shulchan Aruch
Sha'arei Dura was the working code of the Ashkenazi communities from the end of the thirteenth century to the Shulchan Aruch with the Rema's glosses—two and a half centuries and more.
A rare case: a code by a rishon commented upon by acharonim. Glosses on Sha'arei Dura were written by Rabbi Israel Isserlein, the Maharshal, Rabbi Nathan Shapira and the Rema.
There are no exact years. The Jewish Encyclopedia says only that he was active in the second half of the thirteenth century, and notes expressly that his period is still unclear because of possible confusion with other scholars of the same name from the same parts. We set the window by that and write no years.
On the timeline
Related
Sources
Rishonim
- Sha'arei Dura — the code of the forbidden and the permitted in food
Scholarship
- The Jewish Encyclopedia (1906) — the window of activity and the caution about confused names
Basis: documents and evidence.