Catherine Gudelj (plaintiff) and John Gudelj (defendant) were married in 1938. John had an ownership interest in Owl Cleaners, which was dissolved in 1947. Subsequent to the dissolution of Owl Cleaners, during the marriage, John purchased a one-quarter interest in a company called Helene French Cleaners. Testimony at trial showed that John's ownership interest in Owl Cleaners was his separately owned property. When John purchased Helene French Cleaners, he paid the $11,500 purchase price through a $1,500 cash payment made with his separate property and a promissory note for $10,000. At trial, John demonstrated that he had sufficient separate property to purchase Helene French Cleaners from the Owl Cleaners dissolution and the sale of a separate piece of real estate. However, the seller was unaware of John’s separate-property ownership at the time of extending the promissory note. The trial court held that the ownership interest in Helene French Cleaners was John's separate property. Catherine appealed the trial court's decision.