one is in possession for a term and retains possession by an agreement, and is ejected  contrary to it.> If he is kept out by force he has an action on the agreement, and thus  the agreement gives an exception to the possessor and an action to him who does not  possess.1 The possessor has an exception because he enters into possession with the  consent of the plaintiff, because he once wished it though he afterwards ceased to do  so, for it suffices that he once wished it,2 nor may a mutual agreement be dissolved  except by a contrary mutual agreement.3 In all these cases we must see whether the  agreement was satisfied or not, and thus whether he who complains ought to be content  or not.4 If it is agreed that he could enter,5[as above more fully [in the portion]  on gifts,]6 and thus an agreement falls into the assise and by it the assise falls and is  turned into a jury to inquire into the agreement.
The exception against the words he disseised him.
 An exception may be raised against the assise by virtue of the phrase he disseised  him, for it may be alleged that the plaintiff never was in seisin. 7 For he is ejected who  loses possession, not he who was never in possession;89nor is the assise available to  anyone except one who, when he was ejected, possessed, nor is anyone taken to be  ejected except one who possesses,10 in his own name.11 For one may not be disseised  who never had seisin, neither in his own name nor in another's. If in another's, as a  procurator, creditor, farmer or villein, though they have natural possession, the  assise is not available to them if they are ejected, but to the owner, who always has  civil possession and retains natural possession for himself through them.12 And since  to be in seisin is very different from being seised, just as it is very different to be in  possession and to possess,13 we must see who is so seised that he may recover his seisin  and who is not. It is clear that some are in seisin and not seised, as those who possess  in the name of another, as said above; though they are in possession with the consent  of the lords, and though in a way they are seised, with respect to the use and the fruits,  they are not seised as of a free tenement, though they may recover their possession in  a way other than by the assise, as will be explained below.14 There are some who are in  seisin and not seised before [a certain] time, peaceful and long, which may suffice for  title, through the negligence or acquiescence or weakness of lords, as intruders and  disseisors, and others, who, by reason of being conjoined,15 as a husband with his wife  when there are no children of the marriage, or if they have children