1112 - The House of Baden
The House of Baden is established in 1112A.D. when Herman II of the House of Zähringen awards himself the title of Margrave of Baden, named after the family seat of Castle Hohenbaden (pictured), near modern day Baden-Baden.
The Margraviate of Baden was a relatively minor fief, or vassal territory, of the Holy Roman Empire, and over the course of much of its history was divided and reunited according to the internal politics of the ruling family. The main House of Baden (1112 - 1535) spun off the branch of Baden-Hachberg (1190 - 1415), which itself spun off the House of Hachberg-Sausenberg (1306 - 1503). Shortly after the splintered House of Baden was re-united in 1503, it was split again between the houses of Baden-Baden and Baden-Durlach. A short-lived Baden-Rodemarchen branched off temporarily from Baden-Baden, and the House of Baden was once again re-united in 1771 when Baden-Durlach inherited the titles and possessions of Baden-Baden.
Allied with Napoleon Bonaparte in the early 19th Century, Baden was handsomely rewarded with territory and elevation to a Grand Duchy. The map below shows the original Baden territories in red - small parcels of land, around Karlsruhe/Rastatt to the north, and enclosed within the Breisgau to the south - and the extent of Baden's subsequent expansion during the early 19th century.
In the mid-19th century struggle for supremacy within the German Confederation that rose out of the ashes of the Holy Roman Empire, Baden allied first with Austria, then with Prussia, earning itself a place in the Prussian-led German Empire after the unification of Germany in 1871.
Following the First World War Grand Duke Frederick II abdicated and Baden was transformed into the Republic of Baden - part of the German Weimar Republic - with a constitution that was ratified by popular vote, the first such vote in German history.
After Hitler took power in 1933, Baden's elected leaders were replaced with Nazi-appointed officials, and following the fall of France in 1940, Alsace - formerly a French territory across the Rhine with a significant German lineage - was incorporated into the new administrative area of Baden-Elsass. Following the Second World War Alsace was returned to France, and Baden was shared between the French and American occupation forces. Finally, in 1952, the three post-war allied constituted states of Baden, Württemberg-Baden, and Württemberg-Hohenzollern voted to merge, forming the present-day German state of Baden-Württemberg.
The House of Baden survives to this day in the person of Maximilian Andreas Friedrich Gustav Ernst August Bernhard, Margrave of Baden and Duke of Zähringen, first cousin twice removed of the last Grand Duke. His mother was the sister of Prince Philip the Duke of Edinburgh, husband of Queen Elizabeth II, making Maximilian the first cousin of Princes Charles and his siblings (though ineligible to succeed the British throne on account of his marriage to the Catholic Archduchess Valerie of Austria).
Hohenbaden Castle Ruins: von User:Martin-D (Martin Dürrschnabel) [CC-BY-SA-2.5 (http://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons
Baden Map: By ziegelbrenner [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or CC-BY-2.5 (http://creativecommons.org/licenses/by/2.5)], via Wikimedia Commons