Frederick I (German: Friedrich I. von Hohenstaufen, born 1122 in Waiblingen(?); died June 10, 1190 in the Saleph River), also known as Friedrich Barbarossa ("Frederick Redbeard") was elected king of Germany on March 4, 1152 and crowned Holy Roman Emperor on June 18, 1155.

He was also Duke of Swabia (1147-1152, as Frederick III) and King of Italy (1154-1186). As son of Duke Frederick II of Swabia (German Schwaben) and Judith of Bavaria, from the rival House of Guelph (or Welf), Frederick descended from Germany's two leading principal families, making him an acceptable choice for the Empire's princely electors as heir to royal crown.

n 1147 Frederick became duke of Swabia and shortly afterwards made his first trip to the East, accompanying his uncle, the German king Conrad III, on the Second Crusade. The expedition proved to be a disaster, but Frederick distinguished himself and won the complete confidence of the king. When Conrad died in February 1152, only Frederick and the prince-bishop of Bamberg were at his deathbed. Both asserted afterwards that Conrad had, in full possession of his mental powers, handed the royal insignia to Frederick and indicated that he, rather than his own six-year-old son, the future Frederick IV, Duke of Swabia, should succeed him as king. The kingdom's princely electors were persuaded by this account and by Barbarossa's energetic pursuit of the crown and he was chosen as the next German king at Frankfurt on the 4th of March and crowned at Aachen (Aix-la-Chapelle) several days later.

The new king was anxious to restore the Empire to the position it had occupied under Charlemagne and Otto I the Great, and saw clearly that the restoration of order in Germany was a necessary preliminary to the enforcement of the imperial rights in Italy. Issuing a general order for peace, he was prodigal in his concessions to the nobles. Abroad, Frederick intervened in the Danish civil war between Svend III and Valdemar I of Denmark, and negotiations were begun with the East Roman emperor, Manuel I Comnenus. It was probably about this time that the king obtained a papal assent for the annulment of his childless marriage with Adela (Adelheid) of Vohburg (through whom he had gained ownership of much of Alsace), on the somewhat far-fetched grounds of consanguinity (his great-great-grandfather was a brother of Adela's great-great-great-grandmother), and made a vain effort to obtain a bride from the court of Constantinople. On his accession Frederick had communicated the news of his election to Pope Eugenius III, but had neglected to ask for the papal confirmation. Eager to make amends with the Papacy, Frederick concluded a treaty with Rome in March 1153, by which he promised in return for his coronation to defend the papacy and make no peace with king Roger II of Sicily, or other enemies of the Church, without the consent of Eugenius.

He undertook six expeditions into Italy, in the first of which he was crowned Holy Roman Emperor in Rome by Pope Adrian IV, following the suppression by Imperial forces of the republican city commune led by Arnold of Brescia. He left Italy in the autumn of 1155 to prepare for a new and more formidable campaign. Disorder was again rampant in Germany, especially in Bavaria, but general peace was restored by Frederick's vigorous measures. The duchy of Bavaria was transferred from Henry II Jasomirgott, margrave of Austria, who became duke of Austria in compensation, to Frederick's formidable younger cousin Henry the Lion, Duke of Saxony, of the House of Guelph, whose father had already held both duchies. On June 9, 1156 at Würzburg, Frederick married Beatrice of Burgundy, daughter and heiress of Renaud III, becoming King of Burgundy and adding the sizeable realm of the County of Burgundy, then stretching from Besançon (Bisanz) to the Mediterranean, to his possessions.

His uncle, Otto of Freising, wrote an account of Frederick's reign entitled Gesta Friderici I imperatoris (Deeds of the Emperor Frederick). Otto died after finishing the first two books leaving the last two to Rahewin, his provost. Rahewin's description of Frederick, taken from a description of Theodoric II of the Visigoths (453-66) and is from the text Epistles by Apollinar Sidonius "[Frederick's] character is such that not even those envious of his power can belittle its praise. His person is well-porportioned. He is shorter than very tall men, but taller and more noble than men of medium height. His hair is golden, curling a little above his forehead... His eyes are sharp and piercing, his beard reddish, his lips delicate ... His whole face is bright and cheerful. His teeth are even and snow-white in color... Modesty rather than anger causes him to blush frequently. His shoulders are rather broad, and he is strongly built."

After making his peace with the Pope, Frederick embarked on the Third Crusade (1189), a grand expedition in conjunction with the French army, led by king Philip Augustus together with the English, under Richard Lionheart. He organized a grand army and set out on the overland route to the Holy Land, through Hungary, Serbia and Romania, and arrived at Constantinople in the autumn of 1189.

Barbarossa made a short stop in 1189 on his way in the Serbian land of Rascia, where he and his men was received well in Ni? by the Duke of All Serbia Stefan Nemanja. He was taken care by Stefan's son, Prince Rastko; who later became Saint Sava. Frederick got sick in Serbia. According to the legend, St. Sava had healing powers and he healed Frederick, enabling him to continue his quest.

From there they pushed on through Anatolia (where they were victorious in two battles) into Armenia, and approached Syria. The approach of the immense German army greatly concerned Saladin and the other Muslim leaders, who began to rally troops of their own and prepare to confront Barbarossa's forces.

However, on June 10, 1190, Frederick died while crossing the Saleph River in Cilicia, south-eastern Anatolia. The exact circumstances are unknown. He might have taken a refreshing swim, and drowned. It is likely was thrown from his horse and the shock of the cold water caused him to have a heart attack at the age 68. According to the chronicler Ibn al-Athir, he drowned in water that was barely hip-deep, weighed down by his armour.

A more mythological view of Frederick's death is based on the claim that he was an owner of the legendary Spear of Destiny. According to myth, whoever possesses the spear is unstoppable, but if the owner loses the spear, he will soon lose his life also. Frederick died while crossing a stream, and at that moment, some accounts say that the spear had fallen from his hands.

Frederick's death plunged his army into chaos. Leaderless, panicked, and attacked on all sides by Turks, many Germans were killed or deserted. Only 5,000 soldiers, a tiny fraction of the original forces, actually arrived in Acre. Barbarossa's son, Frederick VI of Swabia carried on with the remnants of the army, with the aim of burying the Emperor in Jerusalem, but efforts to conserve his body in vinegar failed. Hence, his flesh was interred in the Church of St. Peter in Antiochia, his bones in the cathedral of Tyre, and his heart and inner organs in Tarsus.

Frederick's untimely death left the Crusader army under the command of the rivals Philip of France and Richard of England, who had traveled to Palestine separately by sea, and ultimately led to its dissolution. Richard Lionheart continued to the East where he fought Saladin with mixed results, but ended without accomplishing his main goal, the capture of Jerusalem.

Frederick is the subject of many legends, including that of a sleeping hero, derived from the much older British Celtic legend of Bran the Blessed. He is said not to be dead, but asleep with his knights in a cave in Kyffhäuser mountain in Thuringia, Germany, and that when ravens should cease to fly around the mountain he would awake and restore Germany to its ancient greatness. According to the story his red beard has grown through the table at which he sits. His eyes are half closed in sleep, but now and then he raises his hand and sends a boy out to see if the ravens have stopped flying.

The German invasion of the Soviet Union in 1941 was codenamed Operation Barbarossa, remembering Frederick I.

Frederick's descendents by his wife Beatrice
1. Frederick V, Duke of Swabia (1164 - 1170)
2. Henry VI, Holy Roman Emperor (November 1165-1197)
3. Frederick VI, Duke of Swabia (1167-1191)
4. Otto II, Count of Burgundy (1170-killed 1200)
5. Conrad II, Duke of Swabia and Rothenburg (1173-killed 1196)
6. Philip of Swabia (1177-killed, 1208) King of Germany in 1198
7. Beatrice of Hohenstaufen (1162-1174). She was betrothed to William II of Sicily but died before they could be married.
8. Agnes of Hohenstaufen (died October 1184). She was betrothed to Emeric of Hungary but died before they could be married.