 The Roman-Dutch law of contract, on the other hand, is based on canon and natural laws.Adopting the canonist position, all contracts were said to be an exchange of promises that were consensual and "bonae fidei", that is, based simply on mutual assent and good faith.Taking the Christian view that it is a sin to break one's promise, canon lawyers developed the "pacta sunt servanda" principle under which all serious agreements ought to be enforced, regardless of whether there had been compliance with strict formalities as prescribed by secular law.