The surety's contract is one of the oldest known to the law; just how old this kind of contract is, it seems impossible to say, except that its origin is of such an ancient date, and some of its characteristics were so well known to the ancients, that it may well be looked upon as an antique among contracts. The essentials of the contract of suretyship include, in addition to the essentials of any valid contract, viz.: that the parties to the contract be competent to contract, that their contract be in the form prescribed by the law, that there be a consideration to support the contract, that its object be lawful, and that the consent given be in no way interfered with by mistake, misrepresentation, fraud, duress or undue influence; the further essential, dictated by the statute of frauds, that the contract agreement be evidenced by a writing, signed by the surety or guarantor, showing the agreement with sufficient definite-ness to identify the parties and to show the terms of the obligation, together, usually, with the naming of the consideration.