As part of Tycho's duties to the Crown in exchange for his estate, he fulfilled the functions of a royal astrologer. At the beginning of each year, he had to present an Almanac to the court, predicting the influence of the stars on the political and economic prospects of the year. And at the birth of each prince, he prepared their horoscopes, predicting their fates. He also worked as a cartographer with his former tutor Anders Sørensen Vedel on mapping out all of the Danish realm. An ally of the king and friendly with Queen Sophie (both his mother Beate Bille and adoptive mother Inger Oxe had been her court maids), he secured a promise from the King that ownership of Hven and Uraniborg would pass to his heirs.