When the unfortunate queen found that all her efforts on behalf of King Charles were in vain, she determined to leave the safe refuge where she had been so hospitably entertained and to return to her husband's side.

She sailed from Scheveningen on March 9, 1643, and reached the royal camp at York in safety.
In the autumn of this year, 1643, two special envoys were sent by Cardinal Mazarin to the Hague; and one of the results of their visit was a renewal of the treaty of 1635 by which France and the United Provinces had entered upon an offensive and defensive alliance and had agreed to conclude no peace but by mutual consent.

Nevertheless Frederick Henry, whom long experience had made wary and far-sighted, had been growing for some little time suspicious of the advantage to the republic of furthering French aggrandisement in the southern Netherlands.

He saw that France was a waxing, Spain a waning power, and he had no desire to see France in possession of territory bordering on the United Provinces.
This feeling on his part was possibly the cause of the somewhat dilatory character of his military operations in 1641 and 1642.

The revolt of Portugal from Spain in December, 1640, had at first been welcomed by the Dutch, but not for long.