page_title: Christen Sørensen Longomontanus
section_title: Publications
hierarchical_section_title: Christen Sørensen Longomontanus / Publications
caption_attribution_description: Italiano: Christiani Severini Longomontani … Inventio quadraturae circuli, nempe I. Symmetriae lineae rectae &amp; circularis longitudine. II. Aequalitatis lineae rectae &amp; circularis III. Rationis diametri circuli ad perimetrum ejusdem. …. - Hafniae&#160;: typis Tychonianis, 1634. - [8], 154, [2] p.&#160;; 4º .
context_page_description: Christen Sørensen Longomontanus was a Danish astronomer.
  The name Longomontanus was a Latinized form of the name of the village of Lomborg, Jutland, Denmark, where he was born. His father, a laborer called Søren, or Severin, died when Christen was eight years old. An uncle took charge of the child, and had him educated at Lemvig; but after three years sent him back to his mother, who needed his help to work the fields. She agreed that he could study during the winter months with the clergyman of the parish; this arrangement continued until 1577, when the ill-will of some of his relatives and his own desire for knowledge caused him to run away to Viborg.
  There he attended the grammar school, working as a labourer to pay his expenses, and in 1588 went to Copenhagen with a high reputation for learning and ability. Engaged by Tycho Brahe in 1589 as his assistant in his great astronomical observatory of Uraniborg, he rendered invaluable service for eight years. Having left the island of Hven with his master, he obtained his discharge at Copenhagen on 1 June 1597, in order to study at some German universities.
context_section_description: His major works in mathematics and astronomy were:
  Systematis Mathematici, etc. (1611)
  Cyclometria e Lunulis reciproce demonstrata, etc. (1612)
  Disputatio de Eclipsibus (1616)
  Astronomia Danica, etc. (1622)
  Disputationes quatuor Astrologicae (1622)
  Pentas Problematum Philosophiae (1623)
  De Chronolabio Historico, seu de Tempore Disputationes tres (1627)
  Geometriae quaesita XIII. de Cyclometria rationali et vera (1631)
  Inventio Quadraturae Circuli (1634)
  Disputatio de Matheseos Indole (1636)
  Coronis Problematica ex Mysteriis trium Numerorum (1637)
  Problemata duo Geometrica (1638)
  Problema contra Paulum Guldinum de Circuli Mensura (1638)
  Introductio in Theatrum Astronomicum (1639)
  Rotundi in Plano, etc. (1644)
  Admiranda Operatio trium Numerorum 6, 7, 8, etc. (1645)
  Caput tertium Libri primi de absoluta Mensura Rotundi plani, etc. (1646)
caption: Inventio quadraturae circuli, 1634
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