In fact, quarrels continually arose, until, at the Peace of Rosahild, in 1658, the duchy was adjudged to Denmark.
"Holstein, however, never acquiesced in this, and in 1675 there was war, when, Holstein being defeated, the Danes imprisoned its duke, Christian Albertus, until he signed a renunciation of all his rights.
"His troops were disarmed, and all his towns and fortresses garrisoned by Danish troops.

On his release, the duke went to Hamburg, where he remained till, at the Peace of Fontainebleau, four years later, he was replaced in possession of his estates and rights of sovereignty.
"But this did not last long.

New troubles arose, but Sweden, England, and Holland interested themselves in favour of the duke, and a peace was concluded in 1689, by which he was confirmed in the rights given him, ten years before, with full liberty to raise a certain number of troops, and of building fortresses, on the condition that he should raise none to the prejudice of Denmark.
"This was another of those stipulations which inevitably lead to trouble, for it afforded to Denmark a pretext for continual complaint and interference.

When Frederick the Fourth succeeded his father as Duke of Holstein, in 1694, the quarrel grew so hot that Denmark would have invaded Holstein, had not the parties to the Treaty of '89 interfered, and brought about a conference.

This lasted all through the year 1696, but the negotiators appointed to settle the matter were unable to arrive at any conclusion.
"The following year, Charles of Sweden, who had just succeeded his father, furnished the duke with some troops, to help him to build some forts that were intended to protect the frontier, in case of invasion by Denmark.