According to the Encyclopædia Britannica, affection developed between Joan and Henry while he resided at the Breton court during his banishment from England.

Joan gave a favourable reply to the proposal, but stated that she could not go through with it until she had set the affairs of Brittany in order and arranged for the security of the duchy and her children.

Finally, she surrendered the custody of her sons and her power as regent of Brittany to the duke of Burgundy, who swore to respect the Breton rights and law, and departed for England with her daughters.

Queen Joan was described as beautiful, gracious and majestic, but also as greedy and stingy, and was accused of accepting bribes.

Reportedly, she did not have a good impression of England, as a Breton ship was attacked outside the English coast just after her wedding.

In August 1419 the goods of her personal confessor, Friar Randolph, were confiscated, although the itemised list shows the objects actually belonged to Joan.

The following month, Randolph came before Parliament and claimed that Joan had "plotted and schemed for the death and destruction of our said lord the King in the most evil and terrible manner imaginable".