Columbus seemed to have a close relationship to Queen Isabella. He was on the royal payroll but it was never clear what Columbus did for the monarchy. A booking entry by a royal accounting clerk shows that the clerk gave money “to Christopher Columbus, foreigner, who is here on Her Majesty’s secret service.” What Columbus was doing on behalf of the queen was a royal secret. According to the Columbus Encyclopedia, Columbus may have been assisting Queen Isabella with the marriage of her daughter to the prince of Portugal between 1488 and 1489. This suggests, but does not prove, that Columbus was from one of the upper classes.