Tycho, a celebrated astronomer, descended of an illustrious family, originally of Sweden, but settled in Denmark, was born on the 14th December 1546, at Knudstorp, in the county of Schonen. He was taught Latin when seven years old, and studied five years under private tutors. His father dying, his uncle sent him, in April 1559, to study philosophy and rhetoric at Copenhagen. The great eclipse of the sun, on the 21st of August 1560, happening at the precise time the astronomers had foretold, he began to look upon astronomy as something divine, and purchasing the Ephemerides of Stadius gained some notion of the theory of the planets. In 1562 he was sent by his uncle to Leipzig to study law; but astronomy wholly engrossed his thoughts, and he employed all his pocket-money in purchasing books on that science. Having procured a small celestial globe, he used to wait till his tutor went to bed, in order to examine the constellations and learn their names; and when the sky was clear, he spent whole nights in viewing the stars. In 1565 a difference arising between Brahe and a Danish nobleman, they fought, and the former had part of his nose cut off, which defect he so artfully supplied with one made of gold and silver, that it was scarcely perceptible. It was about this time that he began to apply to chemistry, proposing nothing less than the discovery of the philosopher's stone. In 1571 he returned to Denmark, and was favoured by his maternal uncle Steno Belle, a lover of learning, with a convenient place at his castle of Herritzval, near Knudstorp, for making his observations, and building a laboratory. But having married a country girl beneath his rank, this occasioned such a violent quarrel between him and his relations, that the king was obliged to interpose in order to reconcile them. In 1574, by his majesty's command, he read lectures upon the theory of comets at Copenhagen; and the year following he began his travels through Germany, and proceeded as far as Venice. He then resolved to remove his family, and settle at Basel; but Frederick II., king of Denmark being informed of his design, and unwilling to lose a man who was capable of proving such an ornament to his country, promised to enable him to pursue his studies, to bestow upon him for life the island of Huen in the Sound, to erect an observatory and laboratory there, and to defray all the expenses necessary for carrying on his designs. Tycho Brahe readily embraced this proposal; and accordingly the first stone of the observatory was laid on the 8th of August 1576. The king also gave him a pension of two thousand crowns out of the treasury, a fee in Norway, and the canonry of Roschil, which brought him in a thousand more. James VI. of Scotland, afterwards raised to the crown of England, going to Denmark in order to marry the Princess Anne, paid a visit to our author in his retirement at Uranienburg, made him several presents, and with his own hand wrote a copy of verses in his praise; but soon after the death of King Frederick he was deprived of his pension, fee, and canonry; upon which, finding himself incapable of bearing the expenses of his observatory, he went to Copenhagen, whither he brought some of his instruments, and continued his astronomical observations in that city, till Valkendorf, chamberlain to the household of Christian IV., by the king's order, commanded him to discontinue them. He then removed his family to Rostock, and afterwards to Holstein, in order to solicit Henry Ranzou to introduce him to the emperor; and that gentleman complying with his request, he was received by the emperor at Prague with the utmost civility and respect. That prince gave him a magnificent house till he could procure one for him better fitted for astronomical observations; assigned him a pension of three thousand crowns; and promised, upon the first opportunity, a fee for him and his descendants. But he did not long enjoy his good fortune; for, on the 24th of October 1601, he died of a retention of urine, in the fifty-fifth year of his age, and was interred in a very magnificent manner in the principal church at Prague, where a noble monument was erected to his memory. His skill in astronomy is universally known, and he is famed as the inventor of a new system, which he endeavoured, though without success, to establish upon the ruins of that of Copernicus. He was very credulous with regard to judicial astrology and presages. If he met an old woman when he went out of doors, or a hare upon the road in a journey, he used to turn back immediately, persuaded that it was a bad omen. When he lived at Uranienburg, he had in his house a madman, whom he placed at his feet at table, and fed with his own hands. As he imagined that every thing spoken by mad persons presaged something, he carefully observed all that this man said; and because it sometimes proved true, he imagined it might always be depended on. A mere trifle put him in a passion; and against persons of the first rank, with whom it was his duty to keep on good terms, he openly discovered his resentment. He was very apt to rally others, but highly provoked if the same liberty was taken with himself. His principal works are, 1. Prognosticata Astronomica, Uranienburg, 1588 and 1589, 2 vols. 4to; 2. De Mundi Ætherici recentioribus phænomenis, 1588, 4to; 3. Epistolorum Astronomicarum libri duo, Francfort, 1610, 4to; 4. Calendarium Naturale Magicum, 1582; 5. Oratio de Disciplinis Mathematicis, Copenhagen, 1610, Svo. His observations were collected by his disciples, and published in 1666 in Historia Coelstis xx. libris.

It was the friendship of Tycho which formed Kepler, and directed him in the career of astronomy. Without this friendship, and without the numerous observations of Tycho, of which Kepler found himself the depositary after the death of his master, he would never have been able to discover those great laws of the system of the world which have been called Kepler's laws, and which, combined with the theory of central forces discovered by Huygens, conducted Newton to the grandest discovery which has ever been made in the sciences, namely, that of universal gravitation.