William IV of Hesse-Kassel (24 June 153225 August 1592), also called ''William the Wise'', was the first

Landgrave Landgrave (german: Landgraf, nl, landgraaf, sv, lantgreve, french: landgrave; la, comes magnus, ', ', ', ', ') was a noble title used in the Holy Roman Empire, and later on in its former territories. The German titles of ', ' (" margrave") ...

of the

Landgraviate of Hesse-Kassel The Landgraviate of Hesse-Kassel (german: Landgrafschaft Hessen-Kassel), spelled Hesse-Cassel during its entire existence, was a state in the Holy Roman Empire that was directly subject to the Emperor. The state was created in 1567 when the La ...

(or Hesse-Cassel). He was the founder of the oldest line, which survives to this day.

Life

Landgrave

William was born in

Kassel Kassel (; in Germany, spelled Cassel until 1926) is a city on the Fulda River in northern Hesse, Germany. It is the administrative seat of the Regierungsbezirk Kassel and the district of the same name and had 201,048 inhabitants in December 2020 ...

, the eldest son of Landgrave Philip the Magnanimous and

Christine of Saxony Christine of Saxony (25 December 1505 – 15 April 1549) was a German noble, landgravine consort of Hesse by marriage to Philip I, Landgrave of Hesse.Eckhart G. Franz (Hrsg.): Haus Hessen. Biografisches Lexikon. (= Arbeiten der Hessischen His ...

. After his father's death in 1567, the

Landgraviate of Hesse The Landgraviate of Hesse (german: Landgrafschaft Hessen) was a principality of the Holy Roman Empire. It existed as a single entity from 1264 to 1567, when it was divided among the sons of Philip I, Landgrave of Hesse. History In the early Midd ...

was divided between the four sons out of the late Landgrave of Hesse's first marriage, and William received the portion around the capital

, the

. William took a leading part in safeguarding the

Lutheran Lutheranism is one of the largest branches of Protestantism, identifying primarily with the theology of Martin Luther, the 16th-century German monk and reformer whose efforts to reform the theology and practice of the Catholic Church launched ...

Reformation The Reformation (alternatively named the Protestant Reformation or the European Reformation) was a major movement within Western Christianity in 16th-century Europe that posed a religious and political challenge to the Catholic Church and in ...

, and was indefatigable in his endeavours to unite the different sections of

Protestantism Protestantism is a Christian denomination, branch of Christianity that follows the theological tenets of the Reformation, Protestant Reformation, a movement that began seeking to reform the Catholic Church from within in the 16th century agai ...

against

Catholicism The Catholic Church, also known as the Roman Catholic Church, is the largest Christian church, with 1.3 billion baptized Catholics worldwide . It is among the world's oldest and largest international institutions, and has played a ...

. However, he was reluctant to use military force in this conflict. As an administrator he displayed rare energy, issuing numerous ordinances, appointing expert officials, and in particular ordering his slender finances. By a law of primogeniture he secured his Landgraviate's land against such testamentary divisions as had diminished his father's estate.

Astronomical work

William is most notable for his

patronage Patronage is the support, encouragement, privilege, or financial aid that an organization or individual bestows on another. In the history of art, arts patronage refers to the support that kings, popes, and the wealthy have provided to artists su ...

of the arts and sciences. As a youth he had cultivated close connections with scholars and as a ruler he kept up this connection. His interest in astronomy may have been inspired by Petrus Apianus's ''

Astronomicum Caesareum ''Astronomicum Caesareum'' (''Astronomy of the Caesars''; also translated as ''The Emperor's Astronomy'') is a book by Petrus Apianus first published in 1540. ''Astronomicum'' was initially published in 1540. Charles V, Holy Roman Emperor, and ...

''. William was a pioneer in

astronomical Astronomy () is a natural science that studies celestial objects and phenomena. It uses mathematics, physics, and chemistry in order to explain their origin and evolution. Objects of interest include planets, moons, stars, nebulae, galaxi ...

research, and perhaps owes his most lasting fame to his discoveries in this branch of study. Most of the mechanical contrivances which made instruments of

Tycho Brahe Tycho Brahe ( ; born Tyge Ottesen Brahe; generally called Tycho (14 December 154624 October 1601) was a Danish astronomer, known for his comprehensive astronomical observations, generally considered to be the most accurate of his time. He was ...

so superior to those of his contemporaries were adopted in

about 1584. From then on the observations made in Hesse-Kassel seem to have been about as accurate as those of Tycho. However the resulting longitudes were 6' too great in consequence of the adopted solar parallax of 3'.

Hessian star catalogue

The principal product of the astronomical observations was the Hessian star catalogue, a catalogue of about a thousand stars. The locations were determined by the methods usually employed in the 16th century, connecting a fundamental star by means of

Venus Venus is the second planet from the Sun. It is sometimes called Earth's "sister" or "twin" planet as it is almost as large and has a similar composition. As an interior planet to Earth, Venus (like Mercury) appears in Earth's sky never f ...

with the sun, and thus finding its longitude and latitude, while other stars could at any time be referred to the fundamental star. It should be noticed that clocks, on which Tycho depended very little, were used at Kassel for finding the difference of

right ascension Right ascension (abbreviated RA; symbol ) is the angular distance of a particular point measured eastward along the celestial equator from the Sun at the March equinox to the ( hour circle of the) point in question above the earth. When pair ...

between Venus and the sun before sunset. Tycho preferred observing the angular distance between the sun and Venus when the latter was visible in the daytime. The Hessian star catalogue was published in ''Historia coelestis'' (Augsburg, 1666) by

Albert Curtz Albert Curtz (''Curtius'' in Latin; 1600, Munich – December 19, 1671, Munich), was a German astronomer and member of the Society of Jesus. He expanded on the works of Tycho Brahe and used the pseudonym of ''Lucius Barrettus''. Background The L ...

, and a number of other observations are to be found in ''Coeli et siderum in eo errantium observationes Hassiacae'' (Leiden, 1618), edited by

Willebrord Snell Willebrord Snellius (born Willebrord Snel van Royen) (13 June 158030 October 1626) was a Dutch astronomer and mathematician, Snell. His name is usually associated with the law of refraction of light known as Snell's law. The lunar crater Sne ...

. R. Wolf, in his ''Astronomische Mittheilungen,'' No. 45 (Vierteljahrsschrift der naturforschenden Gesellschaft in Zurich, 1878), has given a resume of the manuscripts still preserved at Kassel, which throw much light on the methods adopted in the observations and reductions.

Family and children

William was married to

Sabine of Württemberg The Sabines (; lat, Sabini; it, Sabini, all exonyms) were an Italic people who lived in the central Apennine Mountains of the ancient Italian Peninsula, also inhabiting Latium north of the Anio before the founding of Rome. The Sabines divide ...

, daughter of

Christoph, Duke of Württemberg Christoph of Württemberg (12 May 1515 – 28 December 1568), ruled as Duke of Württemberg from 1550 until his death in 1568. Life In November 1515, only months after his birth, his mother, Sabina of Bavaria, fled to the court of her parent ...

.
They had the following children: #

Anna Maria of Hesse-Kassel Anna Maria of Hesse-Kassel (27 January 1567, Kassel – 21 November 1626, Neunkirchen) was a princess of Hesse-Kassel by birth and by marriage Countess of Nassau-Saarbrücken. Life Anna Maria was the eldest daughter of Landgrave William ...

(27 January 156721 November 1626), married on 8 June 1589 to

Louis II, Count of Nassau-Weilburg Louis II of Nassau-Weilburg (9 August 1565, Weilburg – 8 November 1627, Saarbrücken) was a count of Nassau-Weilburg. Life Louis was the eldest son of Count Albert of Nassau-Weilburg-Ottweiler and Countess Anna of Nassau-Dillenburg. H ...

Hedwig of Hesse-Kassel Hedwig of Hesse-Kassel (born 30 June 1569 in Kassel; died: 7 July 1644 in Hagen) was a princess of Landgraviate of Hesse-Kassel, Hesse-Kassel by birth and by marriage a Countess of County of Schaumburg, Schaumburg. Life Hedwig was a daughter of ...

(30 June 15697 July 1644), married on 11 September 1597 to

Ernst of Schaumburg Ernst of Schaumburg (September 24, 1569 – January 17, 1622) was the first Count of Schauenburg and Holstein-Pinneberg to earn the title of Prince in 1619. However, he died in 1622 without an heir. Schauenburg-Pinneberg had been a Lutheran ...

# Agnes of Hesse-Kassel (30 June 15695 September 1569) # Sofie of Hesse-Kassel (10 June 157118 January 1616) #

Maurice, Landgrave of Hesse-Kassel Maurice of Hesse-Kassel (german: Moritz; 25 May 1572 – 15 March 1632), also called Maurice the Learned or Moritz, was the Landgrave of Hesse-Kassel (or Hesse-Cassel) in the Holy Roman Empire from 1592 to 1627. Life Maurice was born in Kassel a ...

(25 May 157215 March 1632), succeeded as landgrave on William IV's death in 1592. # Sabine of Hesse-Kassel (12 May 157329 November 1573) # Sidonie of Hesse-Kassel (29 June 15744 April 1575) # Christian of Hesse-Kassel (14 October 15759 November 1578) # Elisabeth of Hesse-Kassel (11 May 157725 November 1578) #

Christine Christine may refer to: People * Christine (name), a female given name Film * ''Christine'' (1958 film), based on Schnitzler's play ''Liebelei'' * ''Christine'' (1983 film), based on King's novel of the same name * ''Christine'' (1987 fil ...

(19 October 157819 August 1658), married on 14 May 1598 to John Ernst, Duke of Saxe-Eisenach # Juliane, born and died 9 February 1581 In addition William had a few illegitimate children. Most significant and favored among these was Philipp von Cornberg (1553–1616), William's son by Elisabeth Wallenstein. Philipp was ennobled by his father and became the ancestor of the current Barons von Cornberg.

Ancestors

References

External links

Biographical data and references at The Galileo Project

, - {{DEFAULTSORT:William 04, Landgrave of Hesse-Kassel William 4 16th-century German astronomers Scientists from Kassel People from the Landgraviate of Hesse-Kassel 1532 births 1592 deaths Landgraves of Hesse Hesse-Kassel, William IV, Landgrave of