In determining where a cause of action on a promissory note arose, Iowa courts traditionally consider such factors as the place of execution and delivery and the place of payment. See Okey v. Bargenholt, 236 Iowa 423, 19 N.W.2d 212, 214 (1945); Andrew v. Ingvoldstad, 218 Iowa 8, 254 N.W. 334, 336-337 (1934); Jarl v. Pritchett, 190 Iowa 1268, 179 N.W. 945, 946 (1920). Since the defense of the statute of limitations is an affirmative defense, the burden is on the defendant to establish it.