Date: 21 Av 5561
From: Rabbi Moshe Sofer
To: Rabbi Lipman
The responsum refutes the idea that halakha always follows Tosafot, even when the Rif disagrees, emphasizing that the primary halachic authorities are the Rif, Rambam, and Rosh, and clarifies the intent of Maharam of Rothenburg regarding Tosafot's rulings.
Source: Shu"t Chasam Sofer Collected §38