*4331 *432I. The defendants, aside from Mary M. Bebber, who was the widow of Christopher Sigmond, deceased, are the respective purchasers of the land, in pursuance of the sale by her as administratrix, and one Mary Holub, a daughter of the testator,who had received her proportion of the estate as an advancement, and *433she filed, a disclaimer of any interest in the land, and hence has no further interest in the suit. During the adjustment of the pleadings, the court required the plaintiff's to make the petition more specific in certain particulars, on motion of defendants, and complaint is now made of such rulings. The effect of the rulings was to add to and not take from the petition, so that all remains upon which plaintiffs rely to state a cause of action. Nothing added in pursuance of the motions in any way changes the legal effect of the averments relied on by plaintiffs, and as the petition, when amended, was tested, as to its sufficiency, by 'demurrer, there could have been no prejudice because of the rulings on the motions. The objection to the petition is, as shown by arguments, that it does not state facts sufficient to show a cause of action, and, as we have said, the rulings on the motions took nothing from the petition.
2 II. This is a direct, and not a collateral, proceeding. It may be conceded that, if the judgment of the court, ordering the sale of the land to pa.y the mortgage debt, is open to attack in a proceeding other than the one in which it was rendered, this is a proper one. The relief sought is based on a claim that the order of sale made by the district court is void, so far as the homestead is concerned, because of the provisions of the law that the homestead descends to the heirs, and is not liable for the payment of debts of the estate. That rule may be conceded, but we do not understand its operation to defeat the jurisdiction of the court to determine the question, if such an order is sought. In determining the jurisdiction of the court, as to subject-matter, we do not inquire what the law is on the subject, or what the holding should be, but the inquiry is, has the court authority to hear and determine the question? . “Jurisdiction” is thus defined: “Jurisdiction is the authorty by which judicial officers *434take cognizance of and decide causes, or, as it has been most frequently defined, the power to hear and determine the cause. The definition, thus, limited, implies that, if a court having power to hear and determine a cause enters a judgment therein, the validity of such a judgment is not affected by the power of the court to enter the judgment in question.” 12 Am. & Eng. Enc. Law, 244. No modification of this general rule in any way affects the case before us. Great stress is placed on the claim that the law gives no authority for the court to make an order to mortgage real estate for the payment of the debts of an. estate, and it is said that, because of such want of authority, the action of the court in making such an order is void, and, as we understand, because such order was void, the making of the order to sell the land to pay the mortgage is void, and especially so as to a homestead. We cannot understand how the order for the mortgaging of the land can in any way affect the jurisdiction of the district court to order the sale. The application for the order of sale stated the purpose of the sale, and the Whole question was before the court. Nothing more can be said than that the administatrix asked an order of sale for a purpose not authorized by the law. If so, it was the duty of the court to have denied the order, but not to- dismiss the application, because without jurisdiction to determine the question. The determination of the question is precisely what the court should have done, and, had it denied the order, no one would say that it had not jurisdiction to do so. The jurisdiction is as complete for a decision one way as the other, but a decision one way would not be legal, while the other it would. Such an illegality would merely involve error in an authorized proceeding, while an absence of jurisdiction as to subject-matter would nullify the proceeding for any purpose. Appellant cites us to such cases as Deery v. Hamilton, 41 Iowa, 16; McMannis v. Rice *43548 Iowa, 361; Wetherill v. Harris, 67 Ind. 452. A reference to the cases will show they do not bear on the question of jurisdiction, as involved here. In the McMannis Case, the court held that an application for an order to sell real estate by a guardian did not give the court jurisdiction to make an order to mortgage the land. That was because no proceeding was pending for such a-purpose, and the parties were not in court on such an issue. It is not a holding that the court would not have had jurisdiction of the subject-matter had its action, in that respect, been invoked. That the district court had jurisdiction in the matter of the application to sell the real estate, with the parties in court, we have no doubt. If so, the remedy of those not satisfied was by appeal. The facts, now claimed, as ousting the court of jurisdiction, if available .at all, could have been' pleaded in defense, or presented in the way of objections to the granting of such .an order. In Freeman, Judgments (2d ed.) 249, it is said: “An adjudication is final and conclusive, not only as to the matter actually determined, but as to every other matter which the parties might have litigated and have had decided, as incident to, or essentially connected with, the subject-matter of the litigation, and every matter coming within the legitimate purview of the original action, both in respect to matters of claim and defense.” We cited this rule in Donahue v. McCosh, 81 Iowa, 296. See, also, Lamb v. McConkey, 76 Iowa, 47, and Phillips v. Gephart, 53 Iowa, 396. As to the homestead feature, the order would be no more void, because without authority to make it, than would a judgment declaring a lien on a homestead that the law exempted it from. In Collins v. Chantland, 48 Iowa, 241, it is held that, where such a lien was established, and the party was in court and failed to make the defense, he could not resist the enforcement of the judgment upon the ground that the property was exempt from the lien. It is said *436in that case: “Any defense which he had to the claim for a lien made against him should have been made in that .action. * * * The question of the lien is res judicata. His ignorance of his rights at the time the judgment was rendered is no ground for setting it aside.” There is no claim of fraud in obtaining the order of sale. With jurisdiction of the parties and the subject-matter the-remedy of plaintiff was by appeal in that .action. Central Iowa Railway Co. v. Piersol, 65 Iowa, 498. The rule is universal, we think. The judgment will stand affirmed.