Attornment - Civil Litigation. C.C. v. J.B.
In C.C. v. J.B. (Ont CA, 2021) the Court of Appeal stated the basics of attornment:
 The mother brought no motion challenging jurisdiction under r. 16(12) of the Family Law Rules, O. Reg. 114/99. Instead, she took steps in and argued the merits of the underlying motions. She therefore attorned to the court’s jurisdiction by “[taking] steps beyond merely contesting the jurisdiction of [the] court”: Lilydale Cooperative Limited v. Meyn Canada Inc., 2019 ONCA 761, 439 D.L.R. (4th) 385, at para. 52; Kunuthur v. Govindareddigari, 2018 ONCA 730, 427 D.L.R. (4th) 120, at para. 18, leave to appeal refused,  S.C.C.A. No. 449.. UD Trading Group Holding PTE. Limited v. TransAsia Private Capital Limited
In UD Trading Group Holding PTE. Limited v. TransAsia Private Capital Limited (Ont CA, 2021) the Court of Appeal considered an attornment issue:
 Nor does the responding parties’ decision to bring a security for costs motion in this appeal assist the moving parties. Attornment occurs where a party takes steps suggesting they have accepted jurisdiction, which typically are “steps to defend the merits of a proceeding”: Gerard J. Kennedy, “Jurisdiction Motions and Access to Justice: An Ontario Tale” (2018) 55 Osgoode Hall L.J. 79, at p. 103. Attornment does not occur where a party merely contests the jurisdiction of the court: Lilydale Cooperative Ltd. v. Meyn Canada Inc., 2019 ONCA 761, 439 D.L.R. (4th) 385, at para. 52. Nor does it occur where a party takes procedural steps that deal solely with the procedural mechanics of the jurisdiction hearing: Fraser v. 4358376 Canada Inc., 2014 ONCA 553, 324 O.A.C. 68, at para. 15.. Kunuthur v. Govindareddigari
In Kunuthur v. Govindareddigari (Ont CA, 2018) the Court of Appeal succinctly states the essence of attornment:
(ii) Attornment. Capone v. Fotak
 A party attorns to a court’s jurisdiction when it goes beyond simply challenging the jurisdiction of that court and, instead, litigates a claim on the merits: see Van Damme v. Gelber, 2013 ONCA 388 (CanLII), 115 O.R. (3d) 470, at paras. 3, 24, leave to appeal refused,  S.C.C.A. No. 342; and Wolfe v. Wyeth, 2011 ONCA 347 (CanLII), 282 O.A.C. 64, at para. 44.
In Capone v. Fotak (Ont CA, 2022) the Court of Appeal comments on attornment:
 Attornment refers to the situation where a party has, through its actions, agreed to submit to the jurisdiction of the court. Under r. 16.01(2) and r. 17.06(1) of the Rules of Civil Procedure, a party who files a Notice of Intent to Defend is then estopped from asserting that the service should be set aside. When, as here, a party waives any potential defect in service by its conduct in attorning to the jurisdiction or in not moving to set aside service under r. 17.06 before filing a Notice of Intent to Defend, it may not later claim the proceeding is a nullity because it was not served in accordance with the strict requirements of the Convention: Wilson v. Servier Canada Inc., 2000 CanLII 22407 (ON SC), 50 O.R. (3d) 219 (S.C.), at para. 43, leave to appeal to Ont. Div. Ct. refused, 2000 CanLII 29052 (ON SC), 52 O.R. (3d) 20 (Div. Ct.), leave to appeal to S.C.C. refused,  S.C.C.A. No. 88 (S.C.C.).. Fraser v 4358376 Canada Inc.
In Fraser v. 4358376 Canada Inc. (Ont CA, 2014) the Court of Appeal addressed the issue of attornment by an allegedly foreign defendant to the jurisdiction of Ontario courts. Here the defendant had brought a motion to challenge the court's jurisdiction, but also moved to add additional parties to the litigation - a step which necessitated some additional and related legal activity on their part. The Court of Appeal held that these further legal acts, being necessary to have all required parties before the court to resolve the jurisdictional issue, did not constitute attornment:
 We agree with the appellants that the motion judge erred in law by concluding that the steps they took amounted to attornment. In our view, all the steps taken by the appellants are more properly characterized as procedural steps taken within the confines of the jurisdiction motion.
 By asking for a temporary stay, the appellants were asserting their position that proper resolution of their jurisdictional motion required that the corporate defendants be present before the court. The temporary stay they requested was for that specific and limited purpose.
 In our view, a party who challenges the jurisdiction of the court is entitled to insist upon a proper procedural foundation for the determination of the challenge. Provided that the party’s steps request no more than that, they do not amount to attornment.
 As the motion judge decided that the appellants had attorned by seeking a temporary stay, he did not deal with the argument that by asking the court to strike out the amended statement of claim the appellants had attorned. He dealt with that request on the merits and dismissed it.
 We find it difficult to understand how the appellants could ask the court to strike the amended statement of claim on the basis that the amendment had followed the original jurisdiction motion since it was only through the amendment that they became parties with an interest in proceeding with the motion. We agree with the motion judge’s reasons dismissing that motion on its merits. On the issue of attornment, however, we conclude that the motion to strike the statement of claim, although ill-founded, was entirely based and dependent upon the appellants’ contention that the courts of Ontario had no jurisdiction to entertain the claim. Like the motion for the temporary stay, the motion to strike the claim was nothing more than a request to have the jurisdictional motion proceed on a proper procedural foundation.
 We recognize that decisions of this and other courts have taken a broad view of the kind of steps taken in a proceeding that amount to attornment. See, for example: Wolfe v. Pickar, 2011 ONCA 347 (CanLII), 2011 ONCA 347, 332 D.L.R. (4th) 157; Mid-Ohio Imported Car C. v. Tri-K Investments Ltd. 1995 CanLII 2084 (BC CA), (1995), 129 D.L.R. (4th) 181 (B.C.C.A.). However, the test expressed in those cases is whether the party “…appears in court and goes beyond challenging the jurisdiction of the court based on jurisdiction simpliciter and forum non conveniens”: Wolfe v. Pickar, at para. 44 (emphasis added).
 We know of no authority for the proposition that procedural steps brought within the confines of a jurisdiction motion dealing solely with the mechanics of having that motion heard in a proper procedural setting amount to attornment. In our view that is all that occurred in this case. The appellants did not “go beyond challenging the jurisdiction” and the motion judge erred in law in concluding otherwise.