What forum the plaintiff ought to follow; what matters pertain to the secular court.
  that rule fails in [these] cases, because of the difference between jurisdictions and  causes, [Of spiritual and temporal things and their accessories.]3 as in matrimonial  causes and things promised because of marriage, which must be determined in the  ecclesiastical forum because he who has jurisdiction in the principal matter will have  jurisdiction in matters accessory,4 and in the same way if a plea is sued in the secular  forum which belongs to the crown and dignity of the king and faith has been pledged  in the contract, cognisance of the principal matter will not on that account belong to  the ecclesiastical judge. The rule also fails in a testamentary cause and in many other  ecclesiastical causes. By reason of crime, one is sued where he offends, as where he  has committed a crime in another's land,5 for it is where one offends that he is subject  to the law, as may be seen in outfangethef.6 Also by reason of contract, for he who  contracted must be sued where he contracted.7 Also by reason of the thing sought, as  where a clerk claims [against a clerk or a layman] a debt unconnected with a testament  or marriage; he ought to sue in the secular forum. And so if he claims a lay fee,  the action will be before the lord of the fee,8 as an hereditatis petitio by writ of right.  It must be tried before the lord of the fee, or if the lord is negligent, before the sheriff,  because by reason of the negligence of one's proper judge,9 namely, the lord, the plea  is transferred to the county, and then before the king and his justices, for many and  different reasons.10
If a man has chosen one judge he may not easily have recourse to another.
 If one chooses a judge of his own will, he ought not to have recourse to the audience  of another by his own will alone, since he is made his judge by his own consent,11[This  is true unless a royal prohibition causes it to be done, because one cannot alter the  king's jurisdiction by renouncing it to the prejudice of the royal dignity, as will be  explained below.]12 though it is generally true that a judgment given by one not his  proper judge is without effect, since13 it is sometimes to the actor's advantage to bring  the reus before a judge to whose jurisdiction he is made subject by consent, rather  than before him to whom he is subject by reason of his domicile,14 provided that he  has the power of coercion so that he may ensure the execution of his judgment, for if  his proper judge is negligent, the other, though not his proper judge, may be more  diligent.
14. Tancred, 130: quamvis generaliter verum sit quod sententia a non suo iudice lata non tenet . . . quoniam expedit actori convenire reum sub iudice de cuius factus est iurisdictione, magis quam sub eo cui subest domicilii ratione.