Frederick Barbarossa in the context of Prince-elector

Operation Barbarossa was the invasion of the Soviet Union by Nazi Germany and several of its European Axis allies starting on Sunday, 22 June 1941, during World War II. More than 3.8 million Axis troops invaded the western Soviet Union along a 2,900-kilometer (1,800 mi) front, with the main goal of capturing territory up to a line between Arkhangelsk and Astrakhan, known as the A–A line. The attack became the largest and costliest military offensive in human history, with around 10 million combatants taking part in the opening phase and over 8 million casualties by the end of the operation on 5 December 1941. It marked a major escalation of World War II, opened the Eastern Front—the largest and deadliest land war in history—and brought the Soviet Union into the Allied powers.

The operation, code-named after the Holy Roman Emperor Frederick Barbarossa ("red beard"), put into action Nazi Germany's ideological goals of eradicating communism and conquering the western Soviet Union to repopulate it with Germans under Generalplan Ost, which planned for the removal of the native Slavic peoples by mass deportation to Siberia, Germanisation, enslavement, and genocide. The material targets of the invasion were the agricultural and mineral resources of territories such as Ukraine and Byelorussia and oil fields in the Caucasus. The Axis eventually captured five million Soviet Red Army troops on the Eastern Front and deliberately starved to death or otherwise killed 3.3 million prisoners of war, as well as millions of civilians. Mass shootings and gassing operations, carried out by German paramilitary death squads and collaborators, murdered over a million Soviet Jews as part of the Holocaust.

The Third Crusade (1189–1192) was an attempt led by King Philip II of France, King Richard I of England and Emperor Frederick Barbarossa to reconquer the Holy Land following the capture of Jerusalem by the Ayyubid sultan Saladin in 1187. For this reason, the Third Crusade is also known as the Kings' Crusade.

It was partially successful, recapturing the important cities of Acre and Jaffa, and reversing most of Saladin's conquests, but it failed to recapture Jerusalem, which was the major aim of the Crusade and its religious focus.

Simon (fl. 1162) was the Norman Count of Syracuse and a member of the Hauteville family. He may be an illegitimate son of Roger II of Sicily, but more likely a son of Henry, Count of Paterno, the brother-in-law of Roger I. He was probably a descendant of his predecessor Tancred.

In 1162, when Frederick Barbarossa was seeking allies for a planned invasion of the Kingdom of Sicily, he made a treaty with the Republic of Genoa, offering them the entire Ligurian coast and the lands of Simon in Sicily. These lands included the cities of Syracuse and Noto and 250 knight's fees (caballariae) in the fertile plain around Noto, the Val di Noto. When the Emperor Henry VI reissued his father's charter to Genoa on 30 May 1191, he retained the promise of Simon's lands, even though Simon was by then dead.

Frederick II (Italian: Federico, Sicilian: Fidiricu, German: Friedrich, Latin: Fridericus; 26 December 1194 – 13 December 1250) was King of Sicily from 1198, King of Germany from 1212, King of Italy and Holy Roman Emperor from 1220 and King of Jerusalem from 1225. He was the son of Emperor Henry VI of the Hohenstaufen dynasty (the second son of Emperor Frederick Barbarossa) and Queen Constance I of Sicily of the Hauteville dynasty.

Frederick was one of the most brilliant and powerful figures of the Middle Ages and ruled a vast area, beginning with Sicily and stretching through Italy all the way north to Germany. Viewing himself as a direct successor to the Roman emperors of antiquity, he was Emperor of the Romans from his papal coronation in 1220 until his death; he was also a claimant to the title of King of the Romans from 1212 and unopposed holder of that monarchy from 1215. As such, he was King of Germany, of Italy, and of Burgundy. At the age of three, he was crowned King of Sicily as co-ruler with his mother, Constance, Queen of Sicily, the daughter of Roger II of Sicily. His other royal title was King of Jerusalem by virtue of marriage and his connection with the Sixth Crusade. Frequently at war with the papacy, which was hemmed in between Frederick's lands in northern Italy and his Kingdom of Sicily (the Regno) to the south, he was "excommunicated four times between 1227 and his own death in 1250", and was often vilified in pro-papal chronicles of the time and after. Pope Innocent IV went so far as to declare him preambulus Antichristi (forerunner of the Antichrist).

The Duchy of Aosta, originally the County of Aosta (French: Duché d'Aoste), was a realm ruled by the House of Savoy from the early 11th century until the late 18th, when its independent institutions were aligned with those of the Principality of Piedmont. The title "Duke of Aosta" continued to be used by the second sons of the Savoyard monarch. The land of the duchy is today a part of Italy.

The county of Aosta was originally ruled by the bishops of Aosta in the 10th and early 11th centuries. Upon the death of Bishop Anselm in 1026, however, Conrad the Salic ensured that the secular powers of the important Alpine territory passed to the bishop's brother-in-law, his ally Humbert the White-handed, rather than remaining tied to the diocese, which fell to Anselm's unfriendly nephew Burchard. Humbert's son Odo then wed Adelaide, securing the March of Turin. The county was elevated to a duchy by Frederick Barbarossa.

The Archduchy of Austria (Latin: Archiducatus Austriae; German: Erzherzogtum Österreich) was a major principality of the Holy Roman Empire and the nucleus of the Habsburg monarchy. With its capital at Vienna, the archduchy was centered at the Empire's southeastern periphery.

Its present name originates from the Frankish term Oustrich – Eastern Kingdom (east of the Frankish kingdom). The archduchy developed out of the Bavarian Margraviate of Austria, elevated to the Duchy of Austria according to the 1156 Privilegium Minus by Emperor Frederick Barbarossa. The House of Habsburg came to the Austrian throne in Vienna in 1282 and in 1453 Emperor Frederick III, also the ruler of Austria, officially adopted the archducal title. From the 15th century onward, all Holy Roman Emperors but one were Austrian archdukes and with the acquisition of the Bohemian and Hungarian crown lands in 1526, the Habsburg hereditary lands became the centre of a major European power.

The siege of Jerusalem lasted from 20 September to 2 October 1187, when Balian of Ibelin surrendered the city to Saladin. Earlier that summer, Saladin had defeated the kingdom's army and conquered several cities. Balian was charged with organizing a defense. The city was full of refugees but had few soldiers. Despite this fact the defenders managed to repulse several attempts by Saladin's army to take the city by storm. Balian bargained with Saladin to buy safe passage for many, and the city was peacefully surrendered with limited bloodshed. Though Jerusalem fell, it was not the end of the Kingdom of Jerusalem, as the capital shifted first to Tyre and later to Acre after the Third Crusade. Latin Christians responded in 1189 by launching the Third Crusade led by Richard the Lionheart, Philip Augustus, and Frederick Barbarossa separately. In Jerusalem, Saladin restored Muslim holy sites and generally showed tolerance towards Christians; he allowed Orthodox and Eastern Christian pilgrims to visit the holy sites freely—though Frankish (i.e. Catholic) pilgrims were required to pay a fee for entry. The control of Christian affairs in the city was handed over to the patriarch of Constantinople.

Henry VI (German: Heinrich VI.; November 1165 – 28 September 1197), a member of the Hohenstaufen dynasty, was King of Germany (King of the Romans) from 1169 and Holy Roman Emperor from 1191 until his death. From 1194 he was also King of Sicily as the husband and co-ruler of Queen Constance I.

Henry was the second son of Emperor Frederick Barbarossa and Beatrice I, Countess of Burgundy. Well educated in the Latin language, as well as Roman and canon law, Henry was also a patron of poets and a skilled poet himself. In 1186 he married Constance of Sicily. Henry, stuck in the Hohenstaufen conflict with the House of Welf until 1194, had to enforce the inheritance claims by his wife against her nephew Count Tancred of Lecce. Henry's attempt to conquer the Kingdom of Sicily failed at the siege of Naples in 1191 due to an epidemic, with Empress Constance captured. Based on an enormous ransom for the release and submission of King Richard I of England, he conquered Sicily in 1194; however, the intended unification with the Holy Roman Empire ultimately failed due to the opposition of the Papacy. In Sicily, Henry had a reputation for ruthless suppression of political opponents. To this day, he is sometimes given the epithet "the Cruel" (il crudele) by Italian historiographers.

Prince of Orange (or Princess of Orange if the holder is female) is a title associated with the sovereign Principality of Orange, in what is now southern France and subsequently held by the stadtholders of, and then the heirs apparent of, the Netherlands.

The title "Prince of Orange" was created in 1163 by Holy Roman Emperor Frederick Barbarossa, by elevating the county of Orange to a principality, in order to bolster his support in that area in his conflict with the Papacy. The title and land passed to the French noble houses of Baux, in 1173, and of Chalons, in 1393, before arriving with René of Nassau in 1530. The principality then passed to René's cousin, the German-born nobleman from then Spanish Netherlands, William (known as "the Silent"), in 1544. Subsequently, William led a successful Dutch revolt against Spain; however, with independence, the new country became a decentralized republic rather than a unitary monarchy.

The Duke of Brabant (Dutch: hertog van Brabant, French: duc de Brabant) was the ruler of the Duchy of Brabant since 1183/1184. The title was created by the Holy Roman Emperor Frederick Barbarossa in favor of Henry I of the House of Reginar, son of Godfrey III of Leuven (who was duke of Lower Lorraine at that time). The Duchy of Brabant was a feudal elevation of the existing (since 1085/1086) title of landgrave of Brabant. This was an Imperial fief which was assigned to Count Henry III of Leuven shortly after the death of the preceding count of Brabant, Herman II of Lotharingia (born 20 September 1085). Although the corresponding county was quite small (limited to the territory between the rivers Senne and Dender) its name was applied to the entire country under control of the dukes from the 13th century on. In 1190, after the death of Godfrey III, Henry I also became duke of Lotharingia. Formerly Lower Lotharingia, this title was now practically without territorial authority, but was borne by the later dukes of Brabant as an honorific title.

In 1288, the dukes of Brabant became also dukes of Limburg. The title fell to the dukes of Burgundy in 1430. Later on, it followed with the Burgundian inheritance until the French Revolution, although the northern part of the territory of Brabant was actually governed by the United Provinces during the 17th and 18th centuries (see Generality Lands).

An Italienzug (also known as Romfahrt or Romzug in German, or as expeditio italica in Latin) was the expedition undertaken by an elected king of the Romans to be crowned by the pope as Holy Roman Emperor in the city of Rome. Prior to the reforms of Frederick Barbarossa, the kings of the Romans struggled to muster an army for the expedition, for they needed the formal approval of the Reichstag. If such approval was granted, the king had permission to recruit knights for their military service in Italy for 410 days.

However, the nobility was generally disinterested and inclined to rather substitute a monetary payment for the service. Therefore, the small force tended to be composed of mercenaries and high ranking clergymen, reinforced by loyal Italian cities. Occasionally, the substitution was not enough – Henry V ended up using his wife Matilda's dowry to fund his Italienzug.

Frederick Barbarossa was elected King of Germany on 4 March 1152 in Frankfurt am Main. Frederick's uncle, Otto of Freising, was an eyewitness and is the most important source for the 1152 election. According to him, "the entire company of the princes ... from the immense extent of the transalpine realm (as well as certain barons from Italy)" met in Frankfurt by early March to elect a successor to King Conrad III, who had died barely two weeks earlier at Bamberg on 15 February 1152. Only five days after his election, on 9 March, Frederick was crowned in the Aachen Chapel.

The apparent quickness of the election of 1152 contrasts with those of 1125 and 1138. In his own letter to Otto of Freising listing the accomplishments of his first five years on the throne, Frederick does not mention his election, but says only that "we were anointed at Aachen and received the crown of the German realm." According to Otto, Conrad had on his deathbed designated Frederick as his choice of successor, because he knew that the princes would not elect his young son, Frederick. He then entrusted his son and the royal insignia to Frederick.

Judith of Bavaria, Duchess of Swabia (19 May 1100 – 27 August 1130) was a duchess of Swabia by marriage to Frederick II, Duke of Swabia. She was the mother of Frederick I, Holy Roman Emperor, also known as "Barbarossa".

The marquises (also marquesses or margraves) of Saluzzo were the medieval feudal rulers city of Saluzzo (today part of Piedmont, Italy) and its countryside from 1175 to 1549. Originally counts, the family received in feudum the city from the margrave of Turin, Ulric Manfred. It passed to the margrave of Susa, of the del Vasto family of Savona, and, in 1175, it was raised to margravial status by the Emperor Frederick I. In 1549, it was annexed to France during the Italian Wars. It remained under French control until 1601, when it was ceded to the Duke of Savoy in exchange for Bresse and surrounding territories.