The students who were taught Roman law in Bologna (and later in many other places) found that many rules of Roman law were better suited to regulate complex economic transactions than were the customary rules, which were applicable throughout Europe. For this reason, Roman law, or at least some provisions borrowed from it, began to be re-introduced into legal practice, centuries after the end of the Roman empire. This process was actively supported by many kings and princes who employed university-trained jurists as counselors and court officials and sought to benefit from rules like the famous "Princeps legibus solutus est" ("The sovereign is not bound by the laws", a phrase initially coined by Ulpian, a Roman jurist).