On 20 July, Bernadotte sent a letter to his "cousin" Christian Frederik, accusing him of court intrigues and foolhardy adventurism. Two days later he met with the delegation that had been in Norway. They encouraged him to consider Christian Frederik's proposed terms for a union with Sweden, but the Crown Prince was outraged. He reiterated his ultimatum that Christian Frederik either relinquish all rights to the throne and abandon the border posts or face war. On 27 July, a Swedish fleet took over the islands of Hvaler, effectively putting Sweden at war with Norway. The following day, Christian Frederik rejected the Swedish ultimatum, saying that surrender would constitute treason against the people. On 29 July, Swedish forces invaded Norway.