by night or by day,13 a robber or another, where it will be permissible for each to  do right for himself without legal proceedings, with this exception, that if such are  taken alive, life, death and member belong to the king.1415Finally the words  what is due to one are inserted to distinguish it from criminal proceedings; by  the latter I seek not only what is due to me but to every person,16 because of the  king's peace and the common welfare.17
Whence an action arises.
 18We must see whence an action arises. 19It is clear that actions are born of precedent  obligations, as a daughter is born of a mother.20 The obligation, the mother  of the action, takes its own origin and beginning from some precedent cause,  21either ex contractu or quasi ex contractu or ex maleficio or quasi ex maleficio.22  An obligation may arise ex contractu in many ways, as from an agreement, by  questions and answers, from a form of words which brings the wills of the two  parties into accord, as agreements by way of pact, which sometimes are nude,  sometimes vested. If they are nude no action follows, for an action does not arise  from a nude pact.23 A pact must therefore have vestments, of which something is  said below. From24 a cause of this kind, ex contractu or quasi, [the action] will  always be civil. An obligation also arises ex maleficio or quasi, [also ex delicto [or]  quasi ex delicto, [for] injuriae are of several kinds,]ex maleficio,25 as where one  commits the crime of lese-majesty, homicide or theft and the like;26quasi ex maleficio,  as where a judge wittingly renders a false judgment.27 That he is bound is clear, but  because he is bound neither properly ex maleficio nor ex contractu and yet is understood  to have done something wrong, though only through lack of skill, he therefore  is taken to be bound quasi ex maleficio.28
What an obligation is and how it is contracted.
 29Since actions are born of obligations, we must first see what an obligation30  (which takes its being ex contractu or quasi, not ex maleficio or quasi) is, how and  by what words it may be contracted, by what persons it may be acquired and how  it may be extinguished and destroyed; then, when it has been dissolved, how it  may be renewed, how transferred to another person, and how one obligation may  be converted into another. An obligation is a legal bond whereby we are constrained,  whether we wish to or not, to give or do something,31[if one is bound and obligated  to another for something and the other is under a reciprocal obligation to him for  something else, the obligatio is so to speak a contraligatio,]32 and it has four ways by  which it is contracted and several vestments. It is contracted by a thing, by words,  by writing, by consent,33 by traditio [or] by conjunction,34
28. Reading: Obligatus esse videtur, sed quia: Inst. 4.5. pr.: non proprie ex maleficio obligatus videtur. Sed quia neque ex contractu obligatus est et utique peccasse aliquid intellegitur, licet per imprudentiam, ideo videtur quasi ex maleficio teneri ...; cf. Schulz in Seminar, ii, 47