Tycho was born at his family's ancestral seat of Knutstorp Castle (Danish: Knudstrup borg; Swedish: Knutstorps borg),[7] about eight kilometres north of Svalöv in then Danish Scania, now Swedish, to Otte Brahe (of the Brahe family) and Beate Bille (of the Bille family). His twin brother died before being baptized. Tycho wrote a Latin ode to his dead twin,[8] which was printed in 1572 as his first published work. He also had two sisters, one older (Kirstine Brahe) and one younger (Sophia Brahe).

Otte Brahe, Tycho's father, was a nobleman and an important figure at the court of the Danish king. His mother, Beate Bille, came from an important family that had produced leading churchmen and politicians. Both parents are buried under the floor of Kågeröd Church, four kilometres east of Knutstorp. An epitaph, originally from Knutstorp, but now on a plaque near the church door, shows the whole family, including Tycho as a boy.

Tycho later wrote that when he was around age two, his uncle, Danish nobleman Jørgen Thygesen Brahe, "without the knowledge of my parents took me away with him while I was in my earliest youth to become a scholar". Apparently, this did not lead to dispute, nor did his parents attempt to get him back. According to one source,[9] Tycho's parents had promised to hand over a boy child to Jørgen and his wife, who were childless, but had not honoured this promise. Jørgen seems to have taken matters into his own hands and took the child away to his own residence, Tosterup Castle.

Tycho attended Latin school from ages 6 to 12, but the name of the school is not known. It is also thought he may have been taught by a private tutor between these ages. At age 12, on 19 April 1559, Tycho began studies at the University of Copenhagen. There, following his uncle's wishes, he studied law, but also studied a variety of other subjects and became interested in astronomy. The solar eclipse of 21 August 1560, especially the fact that it had been predicted,[10] so impressed him that he began to make his own studies of astronomy, helped by some of the professors. He purchased an ephemeris and books on astronomy, including Johannes de Sacrobosco's De sphaera mundi, Petrus Apianus's Cosmographia seu descriptio totius orbis and Regiomontanus's De triangulis omnimodis. Jørgen Thygesen Brahe, however, wanted Tycho to educate himself in order to become a civil servant, and sent him on a study tour of Europe in early 1562. Tycho was given the 19-year-old Anders Sørensen Vedel as mentor, whom he eventually talked into allowing the pursuit of astronomy during the tour.[11]

Tycho realized that progress in astronomy required systematic, rigorous observation, night after night, using the most accurate instruments obtainable. This program became his life's work. Tycho improved and enlarged existing instruments, and built entirely new ones. His sister Sophia assisted Tycho in many of his measurements. Tycho was the last major astronomer to work without the aid of a telescope, soon to be turned skyward by Galileo and others.

Tycho jealously guarded his large body of celestial measurements, which Kepler took under his care following Tycho's death.

Death of his uncle[edit]
His uncle and foster father, Jørgen Brahe, died in 1565 of pneumonia after rescuing Frederick II of Denmark from drowning. In April 1567, Tycho returned home from his travels and his father wanted him to take up law, but Tycho was allowed to make trips to Rostock, then on to Augsburg (where he built a great quadrant), Basel, and Freiburg. At the end of 1570 he was informed about his father's ill health, so he returned to Knutstorp Castle, where his father died on 9 May 1571.[14] Soon after, his other uncle, Steen Bille, helped him build an observatory and alchemical laboratory at Herrevad Abbey.[14]
2]