delivered the opinion of the court:
On July 17, 1908, plaintiff in error, Sallie M. Thomas, filed her bill for divorce in the superior court of Cook county against defendant in error, Morris St. P. Thomas, on the ground of desertion. An answer was filed on August 21, 1908, denying the charge of desertion, but no mention was made in the bill or answer of the existence of any children of the marriage. On October 29, 1908, the defendant filed his cross-bill, reciting evidence tending to show that he had not deserted his wife but that she had deserted him, which was followed by a statement that she had deserted him and averments that two boys were born of the marriage, Benjamin M. Thomas, then thirteen years old, and Carr M. Thomas, ten years old, and that Benjamin was living with Mr. Thomas and the younger boy, Carr, was with his mother. The cross-bill did not seek a divorce but prayed for the care, custody, education and control of the two children and that Mrs. Thomas be enjoined from interfering therewith, and for such other and further relief as equity might require. Mrs. Thomas answered the allegation of the cross-bill that she had deserted her husband by denying it and demurred to the remainder, which set forth the birth of the children and matters relating to them and their custody. The court overruled the demurrer, and *357Mrs. Thomas electing to stand by it, the cross-bill was ordered to be taken as confessed. When the cause was reached for hearing on the original bill and answer thereto and the cross-bill taken as confessed, Mrs. Thomas moved the court to dismiss her bill without prejudice for want of prosecution, but Mr. Thomas objected and the motion was denied. Mrs. Thomas offered no evidence in support of her bill and the cause was heard upon the cross-bill taken as confessed, but her solicitor appeared and contested the right to a decree on the cross-bill. The solicitor for Mr. Thomas informed the court that a divorce was not wanted, and the relief sought by the cross-bill was the custody of the children. The court entered an order finding that Mr. Thomas was a fit person to have the custody, control and education of the children and giving him the same and enjoining Mrs. Thomas from interfering therewith, and ordering her to bring or send the boy Carr into the State and deliver him to her husband within thirty days. She did not comply with that order, and a final decree was entered dismissing her original bill for divorce, granting the prayer of the cross-bill and adjudging the costs of the suit against Mrs. Thomas. She prayed an appeal to the Appellate Court for the First District, which was allowed and perfected. The Appellate Court affirmed the decree and we granted a writ of certiorari, in pursuance of which the record is now under review.
The original bill prayed for a divorce on the ground of desertion. The cross-bill stated in detail that Mrs. Thomas had gone on a visit to Wisconsin and had not returned to the family home but set up a separate establishment a few blocks distant and had afterward gone to Sioux Falls, South Dakota, all of which was intended to show that the separation was her act, but the cross-bill did not ask for a divorce. Its prayer and its purpose were merely to obtain the care, custody, control and education of the two boys, *358and so much of the cross-bill as alleged facts concerning them and asked for their custody was demurred to on the ground that such matters were not germane to the original bill. Because the original bill stated nothing about the existence of any children of the marriage, it was insisted, by demurrer, that matters concerning their custody could not be made the subject of a cross-bill. The facts set up in the cross-bill were germane to the subject of the original bill in the sense that they related to the same matter. The custody of the, children was necessarily comprehended within the scope of the original bill although nothing was said about them. The filing of the original bill for divorce brought within the jurisdiction of the court the minor children of the parties by virtue of the statute, which authorizes the court, on application, to make such order concerning the custody and care of children during the pend-ency of the suit as may be deemed expedient and for the benefit of the children, and if a divorce shall be decreed the couft may make such order touching the care, custody and support of the children, or any of them, as from the circumstances of the parties and the nature of the case shall be fit, reasonable and just. The cross-bill was not bad on account of the reason alleged in the demurrer, and when the demurrer was overruled Mrs. Thomas was still prosecuting her suit for divorce. The court did not err in overruling the demurrer, but the situation was afterward changed by the motion of Mrs. Thomas to dismiss her bill and her refusal to prosecute it further, and if the court could not grant the relief sought by the cross-bill regardless of the prosecution of the original bill, the decree must be reversed. ° ,
The statute provides' that after a cross-bill has been filed the complainant shall not be permitted to dismiss his bill without the consent of the defendant, and when Mrs. Thomas attempted to dismiss her bill the court denied her *359motion. A cross-bill may be filed purely as a matter of defense based upon facts arising after the cause is at issue. In such a case a defendant cannot avail himself of the defense by plea or answer, but must make it the subject of a cross-bill for the same reason that a complainant can only bring into the suit matters occurring after the filing of his bill by a supplemental bill. (Jenkins v. International Bank, 111 Ill. 462.) The cross-bill in this case was not filed purely as a matter of defense to the bill for divorce based upon facts arising after the filing of the original bill, and if it had been it would not have justified the court in refusing to allow Mrs. Thomas to dismiss her bill. The statute only applies to a cross-bill asking for affirmative relief, since it would be absurd to say that one who is merely defending can insist that the complainant shall remain in court in order that he may make a defense. The court could not compel Mrs. Thomas to prosecute her action for divorce against her will merely in order that Mr. Thomas should have an opportunity to prevent her obtaining it. The cross-bill was for the purpose of obtaining the custody of the children, and a defendant will not be pennitted to file a cross-bill for an object which is equally available by an answer. (Prichard v. Littlejohn, 128 Ill. 123.) Any question relating to the custody of the children could have been raised by Mr. Thomas by his answer, and at any time after the original bill was filed such questions could have been brought before the court by an application for such custody, and upon granting a divorce the court could have awarded the custody to either party. Mr. Thomas could have fully set forth in his answer every tiring that was required for the protection of his rights as father of the children, and so far as the powers of the court under the divorce statute are concerned, the cross-bill was useless. If a defendant should file a cross-bill when he seeks no discovery and no affirmative relief that he cannot obtain by *360answer to the original bill, his cross-bill will be dismissed either on answer or motion or demurrer. (Edgerton v. Young, 43 Ill. 464; Morgan v. Smith, 11 id. 194; Wing v. Goodman, 75 id. 159; Akin v. Cassiday, 105 id. 22; Newberry v. Blatchford, 106 id. 584; Howe v. South, Park Comrs. 119 id. 101.) If the court had no other jurisdiction to award the custody of the children in controversy between the parents than that conferred by the divorce statute, the cross-bill interposed no obstacle to the dismissal of the original bill because Mrs. Thomas declined to prosecute her action for divorce and the cross-bill did not ask for a divorce and none was granted.
In England matrimonial causes were never under the jurisdiction of courts of equity, and in this country the jurisdiction is conferred by statute, which prescribes and limits the powers of the court. So far as the children are concerned, a court can, by virtue of the statute, only make orders concerning their custody during the pendency.of the suit, or upon a final hearing where the divorce is decreed. Some courts have held that the custody of children can be granted to one of the parties to a divorce suit where a divorce is denied, or not granted, which is the same thing, but the decisions rest either on a statute conferring such power or upon supposed general equity powers of the court. In Alabama there is a statute giving courts of chancery power, in all cases of separation between husband and wife where neither party shall obtain a divorce, to give the custody and education of the children either to the father or mother, as -may seem right and proper, and it was held that such an order could be made where there was an ineffectual attempt to procure a divorce. (Cornelius v. Cornelius, 31 Ala. 479.) We have no such statute but our divorce statute is to the contrary, and in this case there was not even an attempt to procure a divorce. In Nelson on Divorce and Separation (vol. 2, 979,) the author says that it is *361not denied that a court has jurisdiction to fix the custody where a divorce is denied in a subsequent proceeding by habeas corpus, and that it seems to him useless to deny the relief in a divorce suit and grant it in another suit for the same purpose in States where the different forms of action are abolished. That opinion, of course, has no application to the courts of this State, where the law-making power has not thought it wise to abolish all distinctions between habeas corpus and bills for divorce nor to authorize courts of equity to administer purely legal remedies. In Power v. Power, 65 N. J. Eq. 93, it was held that when a wife has been denied a divorce the court may award the custody of the children if the bill contains a prayer for 'such relief, but it is quite clear that the court cannot grant such relief under a statute which limits the power of the court to cases where a divorce is granted. The courts generally hold that where a divorce is denied or not granted the court cannot consider or pass upon the question of the custody of the children. (Simon v. Simon, 6 N. Y. (App. Div.) 469, affirmed on the opinion below, 159 N. Y. 549; Keppel v. Keppel, 92 Ga. 506; Garrett v. Garrett, 114 Iowa, 439.) Mr. Thomas could not have maintained, his cross-bill by virtue of any provision of the Divorce act, and if he could not have maintained it under the general equity powers of the court, it was error to refuse leave to dismiss the original bill because the cross-bill had been filed, and the final decree was also erroneous.
A cross-bill which is filed merely as a mode of defense to bring into the case matters occurring after the cause is at issue requires no equity to support it, but a cross-bill which asks affirmative relief is in the nature of an original bill asking further aid of the court beyond the mere defense, and the relief sought must be such as the court, in point of jurisdiction, is competent to administer. (Tobey v. Foreman, 79 Ill. 489; Morrison v. Morrison, 140 id. *362560.) While such a bill must be germane to the subject matter of the original bill, it is, in fact, a separate and distinct suit commenced by the filing of the cross-bill. (Ballance v. Underhill, 3 Scam. 453.) It is an auxiliary suit concerning the same matters involved in the original bill, which is permitted in order that complete justice may be done between the parties in one proceeding. After a court of equity has obtained jurisdiction upon any equitable ground, it will retain such jurisdiction for the purpose of avoiding more than one suit and doing justice between the parties, although in doing so it may be necessary to establish purely legal rights or to grant legal remedies; (Longshore v. Longshore, 200 Ill. 470;) but in order to authorize relief which can be obtained in a suit at law there must be somé substantial ground of equitable jurisdiction, and if there is no equitable ground of jurisdiction and the remedy sought can be as well obtained in an action at law, the court cannot retain jurisdiction and grant a purely legal remedy. Brauer v. Laughlin, 235 Ill. 265.
Mrs. Thomas refused to prosecute her suit for divorce, which she had a right to control, and asked the court to dismiss her bill, which the court" could only refuse to do because the cross-bill had been filed. As already shown, the court could not refuse to dismiss the original bill, under the provisions of the divorce statute, because a cross-bill had been filed which was unnecessary and asked for relief which could not be granted unless the original bill was prosecuted to a decree for divorce. The court proceeded to hear the cause upon the cross-bill, which asked for affirmative relief, by granting to the complainant therein the custody of the children; and if a husband cannot maintain a suit in equity against his wife for such a purpose the court was without jurisdiction and the decree was erroneous.
No case where such a bill has evep been filed in England or this country has been discovered by the careful *363research of the able counsel who have argued this case, and while the fact that it has never been done is not conclusive that it cannot be, it is satisfactory evidence that no solicitor has thought that it could be done. The argument in favor of such jurisdiction is upon the ground that courts of equity have a broad and comprehensive jurisdiction over the persons and property of infants. The existence of such jurisdiction has been frequently asserted in the strongest language, but such declarations are not different from like statements made with reference to jurisdiction over trustees and others occupying fiduciary relations. The jurisdiction can only be exercised when it has been acquired as to the particular person and subject matter in accordance with the practice in courts of equity, which is by the commencement of some sort of recognized proceeding in the court. What has been so often said respecting the jurisdiction does not mean that courts of equity take upon themselves the care, custody, education and maintenance of all the children within the territorial limits where they exercise their powers, but when a suit is instituted in a court of equity relative to the person or property of an infant he is treated as a ward of the court, and the court will not allow his rights to be prejudiced by any act, either of his own or of any other person. The court will protect the infant through a guardian ad litem or otherwise, as may be necessary, and will look to his interests and see that the guardian discharges his duty. (Lynch v. Rotan, 39 Ill. 14; Hartmann v. Hartmann, 59 id. 103; Allman v. Taylor, 101 id. 185; Ames v. Ames, 148 id. 321.) Where some proceeding is instituted in which an infant is a party, either as plaintiff or defendant, the controversy and decision of the court relate to his rights and property, and the court will see that he is represented by guardian, next friend, or in some proper manner, who is entitled to assign error on an improper decision of the court, and in such a proceeding *364the infant becomes a ward of the court. In Greenman v. Harvey, 53 Ill. 386, it was said that an infant who was a party defendant did not become the ward of the court until service of process upon her. The jurisdiction so exercised respecting the rights or property of infants is a part of the general equity juisdiction, but this case is not within those limits. The cross-bill was filed by a husband against his wife to enforce an alleged right of the husband to the custody of the children. The attempt was to have the court consider and determine the relative rights of the parents to such custody, which is not an equitable but a legal right. It is true that where the court has jurisdiction the legal right will not be enforced to the detriment of the child, and the guiding motive of the court will be to conserve and protect the best interests of the child. But the right in question is that of a parent. Neither a want of harmony between a husband and wife relating to the management of their children, nor the right of either to their custody, control, support or education, involves any equitable title or question of an equitable nature. The principles upon which equitable powers are exercised do not sustain the claim that a husband and wife may litigate with each other in a court of equity over the question which one shall have the custody of their children.
There is another power which courts of equity have concerning infants and their property, and that is the appointment of guardians. (Hohenadel v. Steele, 237 Ill 229.) The source of this jurisdiction is quite uncertain. Whether the power was originally a mere usurpation, or was legally delegated to the chancellor by the crown as parens patrice, or grew out of the practice of appointing guardians ad litem, the jurisdiction exists here by inheritance from the English courts of chancery and not because equitable rights of titles are involved. Like the power of any other court to appoint a guardian, that jurisdiction may be exercised upon a proper petition or application for the *365appointment of a guardian. But the cross-bill in this case cannot be regarded as such a petition or application. In Cowles v. Cowles, 3 Gilm. 435, where the parties had been divorced, the court said that the legislature, in providing that when a divorce is decreed the court may award the custody of the children, conferred no new power on the court, which was correct in the sense that the power is of the same nature as a pre-existing power; but the court did not intimate that the power had ever been or could be exercised in a litigation between a husband and wife relating only to the custody of the children.
We conclude that the court had no jurisdiction to award the custody of the children to Mr. Thomas, and that the Appellate Court erred in affirming the decree of the superior court.
The judgment of the Appellate Court and the decree of the superior court are reversed and the cause is remanded to the superior court, with directions to dismiss the original bill and cross-bill.
Reversed and remanded, with directions.