As a result of this failed imprisonment, in 1420 the heirs of Joanna, Countess of Penthièvre surrendered Penthièvre to the Duke, thus ending one element of the Treaty of Guérande designed to favor Joanna and her heirs.
The heirs of Joanna, Countess of Penthièvre surrendered Penthièvre to the Duke, thus ending one element of the Treaty of Guérande. This was as a result of this failed imprisonment. This was in 1420. This Guérande was designed to favor Joanna. This Guérande was designed to favor her heirs.