Stipulations are either judicial, praetorian, conventional, or common: by the latter being meant those which are both praetorian and judicial.

1 Judicial stipulations are those which it is simply part of the judge's duty to require; for instance, security against fraud, or for the pursuit of a runaway slave, or (in default) for payment of his value.

2 Those are praetorian, which the praetor is bound to exact simply in virtue of his magisterial functions; for instance, security against apprehended damage, or for payment of legacies by an heir. Under praetorian stipulations we must include also those directed by the aedile, for these too are based upon jurisdiction.

3 Conventional stipulations are those which arise merely from the agreement of the parties, apart from any direction of a judge or of the praetor, and which one may almost say are of as many different kinds as there are conceivable objects to a contract.

4 Common stipulations may be exemplified by that by which a guardian gives security that his ward's property will not be squandered or misappropriated, which he is sometimes required to enter into by the praetor, and sometimes also by a judge when the matter cannot be managed in any other way; or, again, we might take the stipulation by which an agent promises that his acts shall be ratified by his principal.