In 1152 Frederick I Barbarossa ('Red Beard') became Holy Roman Emperor, and reigned until 1190. His reign was dominated by struggles with the German nobility and the papacy. He mounted a series of campaigns in Italy to capture lands from the pope, and succeeded in capturing Rome in 1167.
In 1144 the Muslims retook Edessa in Asia Minor. A second crusade from Europe to win back Edessa foundered on the long journey eastwards. Soldiers starved, or were ambushed by bandits. Those who reached Asia Minor were destroyed by Turks. In Palestine, Christian rulers competed for power, organizing their resources with the defence of their own territory in mind. In the 1170s Syrian and Egyptian Muslims united under a great warrior, Saladin. In 1187 at the Battle of Hattin, Saladin routed the Christians and took Acre and Jerusalem. In 1189 Richard I of England, German emperor Barbarossa, and King Philip II of France led a third crusade to the east. On his way to Palestine, Barbarossa drowned while swimming in a river. In 1191 Richard recaptured Acre.
According to legend, Barbarossa is not dead but merely sleeping, and will one day wake up to save Germany from disaster.
In 1156 Pope Adrian aroused Frederick against the papacy
by implying in a letter to him that the emperor held lands only as a fief
from the pope
. Two years later Frederick incurred the hostility of the Lombards by demanding recognition of all his royal rights, including his power to appoint the imperial podesta, or governor, in every town. Such cities as Milan, Piacenza, Brescia, and Cremona considered that demand a denial of their communal liberties and in 1158 began a struggle that lasted until 1183 and required Frederick to lead five expeditions to Italy. Between 1158 and 1162 Frederick warred with Milan and its allies, subduing that city and confirming claims to other Italian cities. Meanwhile Frederick had set up a series of antipopes in opposition to the reigning pope, Alexander III, who espoused the cause of the Milanese and their allies and who, in 1165, excommunicated Frederick. By attacking the Leonine City in Rome in 1167-68, Frederick was able to install one of the antipopes, Paschal III, on the papal throne. The Lombard League, consisting of the cities of Milan, Parma, Padua (Padova), Verona, Piacenza, Bologna, Cremona, Mantua (Mantova), Bergamo, and Brescia, was formed in 1167 and eventually acknowledged Pope Alexander as leader. During the next seven years the league acquired military strength, rebuilt Milan, constructed the fortress city of Alessandria, and organized a federal system of administration. The fifth expedition (1174-76) of Frederick to Italy terminated in defeat by the Lombard League at Legnano. The defeat was significant in military history, because it was the first major triumph of infantry over a mounted army of feudal knights. Frederick was forced in 1177 to acknowledge Alexander III as pope and in 1183 to sign the Peace of Constance, acceding to the demands of the Lombards for autonomy but retaining imperial suzerainty over the towns.
Although imperial control in Italy was virtually ended by his defeat at Legnano, Frederick managed to enhance his prestige in central Europe. He made Poland tributary to the empire, raised Bohemia to the rank of a kingdom, and erected the margravate of Austria into an independent hereditary duchy. His own power as emperor in Germany was firmly established in 1180, when he ended his long struggle with the Welfs by putting down a revolt led by the Welf Henry the Lion and depriving him of most of his lands.
Frederick initiated the Third Crusade in 1189, and in the next year, having resigned the government of the empire to his son Henry, later Holy Roman Emperor Henry VI, set out for Asia Minor. After gaining two great victories over the Muslims at Philomelion (now Ak?ehir) and Iconium (now Konya), he was drowned in the Calycadnus (now Göksu) River in Cilicia (now in Turkey) on June 10, 1190.