In the relations with the Dutch the temperate and conservative force in the confederacy was Massachusetts, who took steady ground for peace and opposed hostile measures.  In doing so, however, she went the whole length of nullification and almost broke up the confederacy.  William Kieft, the governor of New Netherland (1637-1647), seemed to recognize at once the significance of the confederacy as well as the importance of making friends with Massachusetts; and in July, 1643, before the commissioners had time to hold their first meeting, he wrote a letter of congratulations to Governor Winthrop, which he loaded, however, with complaints against Connecticut for intruding upon the land of the Dutch fort at Hartford.  Governor Winthrop in reply assured Kieft that the influence of Massachusetts would be on the side of peace, for that “the ground of difference being only a small parcel of land” was a matter of too small value to cause a breach between two people so nearly related as the Dutch and English.

When the federal commissioners met in September they showed a hostile spirit, and addressed vehement letters to the Swedish and Dutch on account of their “foul injuries” offered the New Haven settlers on the Delaware.  In March, 1644, letters came from the Swedes and Dutch full of expressions of regard for the English and “particularly for Massachusetts.”  They promised to refrain from interfering with visitors who should bring authority from the commissioners, which so encouraged some Boston merchants that they sent to the Delaware a pinnace to search for a great lake reported to be its source.  But when they arrived at the Delaware, the Swedish and Dutch governors, while telling the captain that he might go up the river as far as he chose, prohibited him from any trafficking with the Indians, which caused the return of the pinnace to Boston.  After this the war which Kieft provoked with the Indians so occupied the Dutch that for two years they had no time to give attention to their English neighbors.  So hard pressed were they that, instead of making further reclamations on New Haven, they earnestly but unsuccessfully solicited her aid.  After great losses to both the Dutch and the Indians the Mohawks intervened as arbitrators, and brought about a peace in September, 1645.[21]

In 1646 the men of New Haven set up a trading-house near the mouth of the Housatonic, and thereupon Kieft wrote to the commissioners, who met at New Haven in April, 1646, a blustering letter of which the following is a good sample:  “We protest against all you commissioners met at the Red Mount (New Haven) as against breakers of the common league, and also infringers of the rights of the lords, the states, our superiors, in that you have dared, without our express and especial consent, to hold your general meeting within the limits of New Netherland."[22] At the close of Kieft’s administration in 1647 the whole province of New Netherland could furnish not more than three hundred fighting-men and contained a population of not more than two thousand.  Compared with the population of New England these figures seem insignificant enough, and render highly improbable the story popular with some New England historians that the Dutch were enlisted in a great scheme of uprooting the English colonies.