HERBERT CHAMBERS, APPELLANT,

v.

HELEN L. CHAMBERS, APPELLEE

PER CURIAM.

Plaintiff has appealed from an order dismissing with prejudice his complaint for divorce. The grounds alleged in support of his prayer for relief are those of extreme cruelty and constructive desertion. The defendant, appellee here, answered the complaint denying the allegations thereof. One of the defenses interposed in her answer consisted of a motion to dismiss the complaint on the ground that the court lacked jurisdiction over the subject matter of the cause in that the issues upon which plaintiff sought relief had been formerly adjudicated in a proceeding theretofore litigated in the State of Washington. It was alleged that in that proceeding defendant had been the successful party. Defendant attached to her answer a copy of the final decree rendered in the suit previously litigated in Washington.

In advance of the taking of testimony the defendant called up for hearing before the court her motion to dismiss the complaint on the jurisdictional ground plead in her answer. At the hearing on this motion defendant offered and the court admitted in evidence a copy of the complaint filed in the Washington action, together with an affidavit signed by a Washington attorney expressing his- opinion that one of the grounds for divorce litigated in the courts of Washington had been interpreted as being synonymous with one of the grounds for divorce alleged by the plaintiff in the cause then before the court. It was upon consideration of the complaint and the documentary evidence offered in *172support of the motion to dismiss that the court entered the order from which this appeal has been taken.

The complaint in this case was wholly sufficient to state a valid cause of action for divorce under the statutes of Florida. It contained no allegations affirmatively showing, either directly or by inference, that the grounds for divorce sued upon had been formerly adjudicated in any other jurisdiction.

The defendant’s motion to dismiss the complaint was on the stated ground that the court lacked jurisdiction over the subject matter of the cause. The reasons given in support of this ground, and the evidence adduced in proof thereof, relate solely to an affirmative defense of res adjudicata. The record is devoid of any evidence bearing upon the court’s jurisdiction, or lack thereof, over the subject matter of the cause. The order granting the motion and dismissing the complaint was based entirely upon the answer, other pleadings, exhibits and evidence relating to the defense of res adjudicata.

The defense of res adjudicata is affirmative in nature and must be plead in an answer.1 Where, as in this case, the complaint does not allege facts which affirmatively show that the pleader is not entitled to the relief sought because the grounds in support thereof have been formerly adjudicated in another proceeding, such defense cannot be raised by motion for the reason that the plaintiff should not have the burden of anticipating a defense and then overcoming it in his initial pleading.2 The burden is on the defendant to prove his affirmative defenses which cannot be done under the circumstances here present in proceedings on a motion to dismiss.3

It, therefore, follows that the order dismissing the complaint on the ground that the court lacked jurisdiction over the subject matter of the cause was error. The order appealed from is reversed and the cause remanded for further proceedings.

CARROLL, DONALD, K., and WIG-GINTOiN, Judges, concur.

STURGIS, -Chief Judge

(concurring).

I am in full agreement with the law as stated and the conclusion reached by the foregoing opinion. I feel, however, that it unduly emphasizes the fact that the chancellor permitted documentary evidence to be filed before him at the hearing on the motion to dismiss and doubtless considered it in arriving at his decision to grant the motion.

As the order of dismissal does not state the reason therefor, and as it is admitted that the parties were before the chancellor solely on the questions of law presented by the motion to dismiss, rather than on a proceeding for summary decree or for judgment on the pleadings, the propriety of the order must be tested exclusively on the questions of law involved.

Here, as in Hough v. Menses, Fla., 95 So.2d 410, the motion to dismiss was not an answer or a motion for judgment on the pleadings. It is true, of course, that the chancellor apparently considered, though erroneously, the extraneous facts and circumstances reflected by the foreign decree and other papers filed at the hearing, and that this error, immaterial in itself, was the motivating cause, the tangent, by which he was led to commit the material error of granting the motion to dismiss. When all is said and done, however, the only reason why I find error under the facts and circumstances in this case is that the motion, at the time it was acted upon, could only have been tested in its *173relation to the sufficiency of the complaint, standing alone, and that when so tested it should have been denied. All else is irrelevant.

A more detailed and efficient exposition of the phase I have in mind to emphasize will be found by a careful anaylsis of the opinions in Hough v. Menses, supra; Stone v. Stone, Fla.App. Third District, 97 So.2d 352; and in the Author’s Comment to Rule 1.11(b), Florida Rules of Civil Procedure, 30 F.S.A. page 233.