Date: 15 Elul 5598
From: Rabbi Moshe Sofer
To: Rabbi Avraham Teomim
R' Dov signed a comprehensive oath, cherem, and neder pledging never to slaughter or inspect in R' Chaim's territory without R' Chaim's consent, then violated it and claimed the written admission of swearing was false and made under duress. The Chasam Sofer rules R' Dov is bound and should be treated as one who transgressed an oath and cherem, based on the ineffectiveness of amtala in interpersonal disputes (Terumas HaDeshen), the contractual obligation independent of the oath, the Rashba's rule that post-violation amtala is not accepted, and the presumption that R' Dov was sincere at the time of signing.
Source: Shu"t Chasam Sofer YD §9