Two different sources are giving an equation between the Calendar round and the Christian calendar:
Several sources written after the Spanish Conquest (Books of Chilam Balam, Oxcutzcab, de Landa) are reaching different equation between the end of the Katun 13 Ahaw and the corresponding year. Based on this data the end of Katun 13 Ahaw should fall between AD 1536 and 1540.
Current research in Bonn explain the disagreements between the Katun data as a result of back calculation, because the documents are copies from the 17th and 18th century and the knowledge about the calendar was lost (Gunsenheimer 2000, pers. communication).