A promissory note is supposed to be a genuine document acknowledging a loan duly received and promising to pay the same on the date indicated in accordance with the conditions therein set forth. There is no record — is there cannot be — of the number of times such a promise has been fulfilled and the debt discharged. But our casebooks are replete with reports of litigations where the promissory note has been rejected and even indignantly denounced. The usual objection is that it is spurious or fabricated, or vitiated by fraud or duress or undue influence, or not reflective of the true intention of the parties. Article 1169 of the Civil Code explicitly provides: Art. 1169. Those obliged to deliver or to do something incur in delay from the time the obligee judicially or extrajudicially demands from them the fulfillment of their obligation. However, the demand by the creditor shall not be necessary in order that delay may exist: (1) When the obligation or the law expressly so declare; or (2) When from the nature and the circumstances of the obligation it appears that the designation of the time when the thing is to be delivered or the service is to be rendered was a controlling motive for the establishment of the contract; or (3) When demand would be useless, as when the obligor has rendered it beyond his power to perform. In reciprocal obligations, neither party incurs in delay if the other does not comply or is not ready to comply in a proper manner with what is incumbent upon him. From the moment one of the parties fulfills his obligation, delay by the other begins. (Emphasis supplied) WHEREFORE, premises considered, the petition is hereby DENIED for lack of merit. The Court of Appeals' August 30, 2012 Decision and July 15, 2013 Resolution in CA-G.R. SP No. 108617 are hereby AFFIRMED. Criminal Case Nos. 29175-R and 29176-R are hereby REMANDED to the Executive Judge of the Regional Trial Court of Baguio City to be re-raffled to one of its branches other than Branch 7. SO ORDERED. The petitioner argues that the Court of Appeals committed reversible error in the interpretation of the promissory note in light of the established facts. It also erred in not according the said note the presumption of validity as a duly executed public document. Required to submit a comment, the private respondents contended that the assignment of errors raised only questions of fact, the determination of which by the lower courts was as a rule final and conclusive upon this Court. In reply, the petitioner submitted that the erroneous findings of fact made by the respondent court removed the case from the general rule and justified a review of the challenged decision. The Court has gone over the records of this case and finds that there was indeed a misapprehension of facts by the trial and appellate courts. The testimonies of the private respondents on the circumstances surrounding the execution of the promissory note are, in our view, not believable. The Rules of Court provide that "when the terms of an agreement have been reduced to writing, it is to be considered as containing all such terms, and, therefore, there can be, between the parties and their successors in interest, no evidence of the terms of the agreement other than the contents of the writing." 3 It is true that parol evidence may be admitted to challenge the contents of such agreement "where a mistake or imperfection of the writing, or its failure to express the true intent and agreement of the parties, or the validity of the agreement is put in issue by the pleadings." 4 However, such evidence must be clear and convincing and of such sufficient credibility as to overturn the written agreement. The private respondents are not unlettered peasants with a modicum of intelligence and unfamiliar with business and legal matters. They are educated persons with not a little experience in business affairs and possibly even legal transactions. They own and operate an hacienda consisting of 33 hectares. Epifania Ebarle was a professor in English for 25 years at the Silliman University. Sol Ebarle holds a degree in commerce, Ele Ebarle in agriculture. There is no question that these three professionals fully understood the import and consequences of what they were doing when they signed the two promissory notes on September 8, 1984.