On January 16, 1959, a writ of habeas corpus was issued. The petition was made by Mary Louise Zillmer of Lindsborg, Kansas, in her own behalf, and on behalf of her children David and Victor. The respondents named in the writ were Herman E. and Florence Zillmer of Washburn county, Wisconsin, the paternal grandparents. It was alleged that they were unlawfully detaining David, age five, and Victor, age three.

These children were born to Mary Louise Zillmer and Herman L. Zillmer, her husband, while they were living in Kansas. While Mary Louise was confined in a hospital in Kansas by reason of mental illness, Herman L. Zillmer had turned the children over to his parents, who kept them at their home in Wisconsin.

After being legally restored to capacity by order of a probate court in Kansas on July 9, 1958, Mary Louise brought action for divorce in a district court in Kansas. When the matter was heard on December 8, 1958, and January 8, 1959, Herman L. Zillmer did not appear. The district court found, however, that Herman L. Zillmer was a resident of Kansas when the action was filed, and had been duly notified of the action by personal service, and had entered his appearance by written answer; that Mary Louise had been adjudicated an incompetent person on July 26, 1955, but had been legally restored to competency; "That the two minor children of the parties hereto are now with their grandparents in the state of Wisconsin. That they were taken there by the defendant without the knowledge or permission of the plaintiff and no court has given custody of these children to the grandparents. The parties herein both continued their Kansas residence after said children were taken by the defendant to Wisconsin. That these two children thereby remained and are now residents of Kansas and are now subject to the jurisdiction of this court for the purposes of determining their custody." Judgment was entered January 8, 1959, granting Mary Louise a divorce, custody of the children, and monthly support money to be paid by her husband.

The petition for the writ of habeas corpus included an allegation that Mary Louise has a proper and fitting home for the children. Testimony was introduced, tending to support this allegation, and it was not disputed.

The grandparents, in their return, alleged that it is unsafe for the children to be in the custody of Mary Louise, and that she is likely to have a recurrence of her mental illness and may harm or kill the children. Herman L. Zillmer gave testimony on behalf of his parents, tending to show that in 1946, prior to marriage, Mary Louise had attacked her mother with a knife, and had been in the hospital for a period, receiving shock therapy; that in 1953, after David was born, she was again treated by a psychiatrist and given shock therapy; that in 1954, she acquired some unusual religious beliefs and admitted that at about that time, she had attempted to shoot her husband, but was unsuccessful because she was unable to prepare the gun properly for firing; that after Victor was born in 1955, it was necessary for her to be a volunteer patient at the state hospital for a few weeks; that after her return home, she attempted to strangle the baby, saying that the child was damned because of the religious differences between her and her husband. On July 20, 1955, she was committed to the state hospital where she remained until released on parole in the spring of 1957.

On July 9, 1958, she was discharged from the state hospital as "restored to capacity," and the order of the probate court restoring her to capacity was entered the same day.

The grandparents called a physician as an expert witness. In answer to a hypothetical question, based upon the facts above referred to, he testified that the mental illness described is psychotic; that psychotics are incurable from the standpoint of recurrence and that, "if her nervous breakdown occurs again, which it most likely will, in my opinion, she most likely will injure the children because she has threatened to in the past."

After hearing, the circuit court made findings of fact, including findings that Mary Louise, her husband, and the two children were subject to the jurisdiction of the district court of Saline county, Kansas, on January 8, 1959, for the purpose of determining custody; that the Kansas divorce action was res judicata, and that Mary Louise was competent at the time the divorce was granted, and at the time of the hearing on habeas corpus. There was no finding expressly as to the best interests of the children. Judgment was entered March 9, 1959, awarding custody to Mary Louise. The grandparents moved for review and reconsideration, but except for minor amendments to the findings, the motion was denied, and judgment awarding custody to Mary Louise was again entered on April 3, 1959. Upon application of the grandparents, this court issued a writ of error.

FAIRCHILD, J.

In Greef v. Greef (1959), 6 Wis.2d 269, 94 N.W.2d 625, we noted with approval a tentative draft of the Restatement, Conflict of Laws, which proposed recognition of three bases for jurisdiction over the custody of children: (1) Domicile of the child within the state, (2) physical presence of the child within the state, and (3) personal jurisdiction over the parties contending for custody. In the present circumstances, Wisconsin meets the second and third tests and Kansas at the time of the divorce judgment met the first and third. A habeas corpus proceeding is appropriate in Wisconsin for the adjudication of legal custody. Bellmore v. McLeod (1926), 189 Wis. 431, 207 N.W. 699; State ex rel. Hannon v. Eisler (1955), 270 Wis. 469, 71 N.W.2d 376; sec. 48.15, Stats.

The next question is whether the Kansas judgment was res judicata, or whether the Wisconsin court could, or should have made a fresh determination whether custody of the mother or of the grandparents would promote the best interests of the children. It would seem, upon general principles, that since the Kansas court had jurisdiction of the subject matter and of the parents, its decision would be conclusive.

The grandparents contend that the Kansas judgment is not res judicata because they were not parties to the action in Kansas. This argument suggests that the grandparents had a personal right to custody and control of the children which could not be dealt with by a court not having personal jurisdiction over them. It is true that the supreme court of the United States has held that a second state need not recognize the custody decree of the first state where the first state did not have personal jurisdiction over the parent being deprived of custody. May v. Anderson (1953), 345 U.S. 528, 534, 73 Sup. Ct. 840, 97 L.Ed. 1221. Although the children were in the immediate care and control of the grandparents when the Kansas judgment was entered, the circumstances do not suggest that the children had been abandoned by the parents, nor that the grandparents in any other way acquired personal rights in the nature of parental rights. As far as parental rights were concerned, the adjudication in Kansas settled the matter.

The grandparents also contend that the issue of the welfare of the children was before the circuit court, notwithstanding the Kansas judgment. They are correct, of course, in pointing out that the welfare of the child is the controlling consideration in custody matters. Bellmore v. McLeod, supra; Pollock v. Pollock (1956), 273 Wis. 233, 243, 77 N.W.2d 485.

Whether in the absence of a change in circumstances the Kansas judgment on custody is binding on the Wisconsin court by reason of the constitutional requirement that full faith and credit be given has been expressly left undecided by the United States supreme court. State ex rel. Halvey v. Halvey (1947), 330 U.S. 610, 67 Sup. Ct. 903, 91 L.Ed. 1133; Kovacs v. Brewer (1958), 356 U.S. 604, 78 Sup. Ct. 963, 2 L.Ed.2d 1008. Nevertheless, it has been the rule in this state that a substantial change in circumstances must be established in order to warrant a change in the custody of children. State ex rel. Hannon v. Eisler, supra.

The grandparents assert that a judgment as to custody may also be modified because of facts existing but not disclosed to the court when the original order was made. They cite 17A Am. Jur., Divorce and Separation, p. 31, sec. 838, which supports their position with the explanation that the public interest in promoting the welfare of the child has frequently been allowed to temper the harsh application of the rule of res judicata, but indicates that some courts do not agree. It is logical that the interest of the child and of the public in the child's welfare should not be concluded by the failure of the parents to bring relevant and important facts to the attention of the court. From the record before us, it appears that the mother's mental illness, her restoration to capacity, and the presence of the children in the care of the grandparents were all brought to the attention of the Kansas court. It does not appear whether any of the details of her illness were disclosed. It may be true that the Kansas court would have been aided by more-searching inquiry into the prognosis of the mother's illness. The facts presented, however, did at least suggest the question of whether the mother's illness might affect her fitness to have custody.

In any event, even if under some of the principles contended for by the grandparents the Wisconsin court is not bound by the Kansas judgment, we think that as a matter of discretion, the Wisconsin court should defer to the Kansas court in these circumstances. Little more than one week elapsed between the Kansas judgment and the commencement of the habeas corpus proceeding here. It would have been more orderly to have fully presented the question of custody to the Kansas court. It has not been shown nor suggested, that any provision of Kansas law or procedural rules would have prevented the presentation of the medical testimony to the Kansas court, either before judgment, or upon an application for reopening and reconsideration thereof. If the Kansas court would not have recognized the standing of the grandparents to bring the facts before it, it undoubtedly would have recognized the standing of the father of the children to do so. It is evident that he was willing to cooperate with his parents; he traveled from Washington, D.C., where he is now employed, to be a witness in the proceeding in Wisconsin. He admitted receiving notice of the divorce action and employing counsel to appear for him. He offered no explanation why he had not opposed the award of custody before the Kansas court.

By the Court. — Judgment affirmed.

MARTIN, C. J., took no part.

The following opinion was filed March 8, 1960:

PER CURIAM (on motion for rehearing).

Counsel for the grandparents, plaintiffs in error, again forcefully urges that the judgment subjects the children to great danger.

Counsel asks that we remand the case for the appointment of a guardian ad litem and (at the expense of plaintiffs in error) of medical experts, and that if such experts desire to examine the mother, she come to Wisconsin for such examination at the expense of plaintiffs in error. The fundamental difficulty with the suggestion is that it contemplates, in effect, a new trial in the Wisconsin circuit court of an issue which was decided, even if not upon presentation of all the evidence, in the Kansas district court. This seems particularly inappropriate where the action in Wisconsin was commenced little more than one week after the Kansas judgment, where the mother, the party entitled to custody under the Kansas judgment, would be compelled to fight her battle at a great distance from her home, and where the doctors who observed and treated her, and the medical records are far away in Kansas.

Further reflection has not altered our conclusion that the question of custody ought to be decided in the Kansas court, and counsel has not attempted to show that the law of Kansas would prevent further consideration there. Because of the concern for the' welfare of the children engendered by the opinion of the medical witness, however, we have concluded that it will be an appropriate exercise of the power of the Wisconsin court to permit the children to remain in the temporary custody of the grandparents pending institution and disposition of an application to the Kansas court for modification of its judgment in so far as it relates to custody. This will necessitate modifying our mandate so as to reverse the judgment of the circuit court and to give directions to the circuit court so as to effectuate the purpose just mentioned as follows: The children are to remain in the temporary custody of the grandparents for a period of sixty days from the filing of the remittitur from this court. If, within that time, plaintiffs in error shall have made satisfactory proof before the circuit court that either they, or Herman L. Zillmer, or all of them, have made an appropriate application to the district court of Saline county, Kansas, for the modification of the portion of its judgment providing for custody of the children, then the circuit court shall permit the plaintiffs in error to retain temporary custody of the children until such time as the district court denies the application, or modifies its judgment. The circuit court may make reasonable provisions for Mary Louise Zillmer's visiting the children. If the period of sixty days elapses without proof that the said application has been made, the circuit court is to reinstate its judgment of April 3, 1959, awarding custody to Mary Louise Zillmer. If the application is made but the district court declines to modify its judgment, or if the circuit court at any time finds that the application for modification is not being diligently prosecuted, then the circuit court is to reinstate its said judgment. If the district court in Kansas modifies its judgment with respect to custody, then the circuit court is to enter a judgment herein not inconsistent with the judgment of the district court as modified.

Accordingly, our mandate herein is amended so as to read

Judgment reversed; cause remanded for further proceedings not inconsistent with the memorandum on rehearing filed herein. No costs allowed to either party in this court.