Understanding how language is used in specific contexts and the reasons for this can be helped by examining historical change in genres. In this study focusing on business communication, texts serving the same purpose of demanding payment for a debt but separated by 4,000 years are analysed. The ancient text is a Sumerian cuneiform tablet which is compared to two modern model business letters. The texts are investigated through a genre analysis focusing on functions and linguistic features and a multidimensional register analysis. Both analyses produce similar results with the main exception being the sequencing of functions. The lack of much meaningful change in business communication in the last 4,000 years is likely to be due to the dominant influence of communicative purposes in guiding how language is used.