Archduke Karl Ludwig Joseph Maria of Austria (30 July 1833 – 19 May 1896) was the younger brother of Franz Joseph I of Austria (1830-1916), the father of Archduke Franz Ferdinand of Austria (1863-1914), whose assassination ignited World War I, and grandfather of the last emperor,  Charles I.
He was born at
Schönbrunn Palace in Vienna, the son of Archduke Franz Karl of Austria (1802-1878) and his wife Princess Sophie of Bavaria (1805-1872).
His mother ensured he was raised a devout Roman Catholic by the Vienna Prince-archbishop
Joseph Othmar Rauscher, a conviction that evolved into religious mania in his later years.
Though not interested in politics, the 20-year-old joined the
Galician government of Count Agenor Romuald Go?uchowski and in 1855 accepted his appointment as Tyrolean stadtholder in Innsbruck, where he took his residence at Ambras Castle. However, he found his authority to exert power restricted by the Austrian cabinet of his cousin Archduke Rainer Ferdinand and Baron Alexander von Bach. He finally laid down the office upon the issue of the 1861 February Patent for a life as patron of the arts and sciences.
As the eldest surviving brother of the Emperor, Karl Ludwig, after the death of his nephew Crown Prince
Rudolf of Austria in 1889, became heir presumptive to the Austro-Hungarian Empire. A newspaper article appeared shortly after the death of his nephew claiming that the Archduke had renounced his succession rights in favor of his eldest son Franz Ferdinand. This rumor proved to be false.  
Marriage and family
Princess Margaretha of Saxony
Princess Maria Annunciata of Bourbon-Two Sicilies, Archduchess of Austria
Karl Ludwig and his third wife, Maria Teresa of Portugal
Karl Ludwig married three times.
His first wife, whom he married on 4 November 1856 at
Dresden, was his first cousin Margaretha of Saxony (1840-1858), the daughter of Johann of Saxony (1801-1873) and Amalie Auguste of Bavaria (1801-1877). She died on 15 September 1858 and they had no children.
His second wife, whom he married by proxy on 16 October 1862 at
Rome, and in person on 21 October 1862 at Venice, was Princess Maria Annunciata of Bourbon-Two Sicilies (1843-1871), daughter of Ferdinand II of the Two Sicilies (1810-1859) and Maria Theresa of Austria (1816-1867).
They had four children:
Maria Annunciata died on 4 May 1871.
His third wife, whom he married on 23 July 1873 at
Kleinheubach, was Infanta Maria Theresa of Portugal (1855-1944), daughter of Miguel I of Portugal (1802-1866) and Adelaide of Löwenstein-Wertheim-Rosenberg (1831-1909).
They had two daughters:
Karl Ludwig died of
typhoid at Schönbrunn in Vienna returning from a journey to Palestine and Egypt, allegedly after the consumption of contaminated Jordan waters. His widow, Maria Teresa died on 12 February 1944.
Honours Austrian decorations  Foreign decorations 
Baden: Knight of the House Order of Fidelity, 1873 
Kingdom of Bavaria: Knight of St. Hubert, 1853 
Belgium: Grand Cordon of the Order of Leopold, 1853; wedding gift of King Leopold I in honour of his son and daughter-in-law. 
Empire of Brazil: Grand Cross of the Southern Cross
Duchy of Brunswick: Grand Cross of Henry the Lion
Denmark: Knight of the Elephant, 21 July 1890 
Ernestine duchies: Grand Cross of the Saxe-Ernestine House Order
French Empire: Grand Cross of the Legion of Honour
Kingdom of Greece: Grand Cross of the Redeemer
Grand Duchy of Hesse: Grand Cross of the Ludwig Order
Kingdom of Italy: Knight of the Annunciation, 21 September 1873 
Mexican Empire: Grand Cross of the Mexican Eagle
Nassau Ducal Family: Knight of the Gold Lion of Nassau
Netherlands: Grand Cross of the Netherlands Lion
Ottoman Empire: Order of Osmanieh, 1st Class in Diamonds
Persian Empire: Order of the August Portrait, in Diamonds
Kingdom of Portugal: Grand Cross of the Tower and Sword
Kingdom of Prussia:
Kingdom of Romania: Grand Cross of the Star of Romania
Saxe-Weimar-Eisenach: Grand Cross of the White Falcon
Kingdom of Saxony: Knight of the Rue Crown
Principality of Serbia: Grand Cross of the Cross of Takovo
Siam: Knight of the Crown of Siam, 1st Class, in Diamonds
Spain: Grand Cross of the Order of Charles III
Sweden-Norway: Knight of the Seraphim, 7 January 1870  Württemberg: Grand Cross of the Württemberg Crown
Ancestors of Archduke Karl Ludwig of Austria
^ "Franz Ferdinand, Archduke of Austria."
Encyclopedia of World Biography. Vol. 29. Detroit: Gale, 2009. Gale Biography In Context. Web. 18 May 2012.
"The Crown Prince's Successor". . 1889-02-02. The New York Times
"Austria's Insecurity" (PDF). The New York Times. 1896-06-16.
^ a b
Hof- und Staats-Handbuch der Österreichisch-Ungarischen Monarchie (1896), Genealogy p. 2
Boettger, T. F. "Chevaliers de la Toisón d'Or - Knights of the Golden Fleece". La Confrérie Amicale . Retrieved 2019.
"A Szent István Rend tagjai" Archived 22 December 2010 at the Wayback Machine
Hof- und Staats-Handbuch des Großherzogtum Baden (1876), "Großherzogliche Orden", p. 59
Hof- und Staats-Handbuch des Königreichs Bayern (1873), "Königliche-Orden" p. 9
^ Le livre d'or de l'ordre de Léopold et de la croix de fer, Volume 1 /Ferdinand Veldekens
Jørgen Pedersen (2009). (in Danish). Syddansk Universitetsforlag. p. 472. Riddere af Elefantordenen, 1559-2009 ISBN . 978-87-7674-434-2
Italia : Ministero dell'interno (1884). . Unione tipografico-editrice. p. Calendario generale del Regno d'Italia 47.
(in Swedish), 1877, p. 368 Sveriges statskalender , retrieved – via runeberg.org
^ a b
Wurzbach, Constantin, von, ed. (1860). . [ Biographisches Lexikon des Kaiserthums Oesterreich Biographical Encyclopedia of the Austrian Empire] (in German). 6. p. 257 – via Wikisource.
^ a b
Wurzbach, Constantin, von, ed. (1861). . [ Biographisches Lexikon des Kaiserthums Oesterreich Biographical Encyclopedia of the Austrian Empire] (in German). 7. p. 149 – via Wikisource.
^ a b
Wurzbach, Constantin, von, ed. (1860). . [ Biographisches Lexikon des Kaiserthums Oesterreich Biographical Encyclopedia of the Austrian Empire] (in German). 6. p. 208 – via Wikisource.
^ a b
Wurzbach, Constantin, von, ed. (1861). . [ Biographisches Lexikon des Kaiserthums Oesterreich Biographical Encyclopedia of the Austrian Empire] (in German). 7. p. 81 – via Wikisource.
^ a b
[ Genealogie ascendante jusqu'au quatrieme degre inclusivement de tous les Rois et Princes de maisons souveraines de l'Europe actuellement vivans Genealogy up to the fourth degree inclusive of all the Kings and Princes of sovereign houses of Europe currently living] (in French). Bourdeaux: Frederic Guillaume Birnstiel. 1768. p. 94.
^ a b
"Karoline Friederike Wilhelmine Königin von Bayern". Haus der Bayerischen Geschichte [House of Bavarian History] (in German). Bavarian Ministry of State for Wissenschaft and Kunst . Retrieved 2018.