Terumat HaDeshen : Rabbi Yisrael Isserlein

Terumat HaDeshen is written as 354
responsa. 354 is the numerical value of
Deshen.
Terumat HaDeshen serves as an important source of the practices of the Ashkenazi Jews. The work was therefore used by Rabbi Moshe Isserles as one basis for HaMapah - the component of the Shulkhan Arukh which specifies
divergences between Sephardi and
Ashkenazi practice.

Also included, his commentary on the Torah.