Frederick was the eldest son of King
Vladislav II of Bohemia and
Gertrude of Babenberg, a daughter of Margrave
Leopold III of Austria. His father had ruled as a
Bohemian duke since 1140; in 1158 he obtained the royal title by the
Hohenstaufen emperor
Frederick Barbarossa, godfather and namesake of Frederick. His elevation expressed the emperor's gratitude for Vladislav's loyalty and faithful service; he thereby became the second Přemyslid king after his grandfather
Vratislav II (d. 1092). His son Frederick ruled as a
Moravian prince of
Olomouc from 1164 onwards. King Vladislav's relations with the emperor deteriorated when in 1172 he abdicated in favour of Frederick, trying to implement a line of succession in accordance to the principle of
agnatic seniority, but without consulting Barbarossa. While the
Prague throne was claimed by Vladislav's cousins, sons of the late Duke
Soběslav I, Frederick was unable to hold on to his duchy, as his tenancy was approved by neither the Bohemian
diet nor the emperor. Father and son were eventually declared deposed in September 1173 by the emperor at an
Imperial Diet in
Hermsdorf (Erbendorf). In agreement with the Bohemian nobility, Barbarossa offered the throne to Vladislav's cousin
Oldřich. However, Oldřich declined the honour and renounced the rule over Bohemia in favour to his elder brother
Soběslav II, who was sympathetic to the peasantry. While aged Vladislav II left Bohemia and retired to the
Thuringian estates of his second wife
Judith, Frederick had to serve at the Imperial court. Nevertheless, Soběslav II turned out antagonistic to both the Bohemian nobles and the emperor. He was reluctant to support Barbarossa on his
Italian campaign against the
Lombard League, where the Imperial forces suffered a major defeat in the 1176
Battle of Legnano. Moreover, Duke Soběslav campaigned the
Babenberg lands of
Austria in the south, whereby Duke
Henry Jasomirgott, Barbarossa's uncle, was killed in an accident. While Soběslav ignored a summons to appear at the Imperial court, Frederick was able to forge an alliance with the Moravian prince
Conrad III Otto of Znojmo and the Babenberg duke
Leopold V of Austria. Backed by Emperor Barbarossa, they marched against Prague where Frederick was elected duke in 1178. First attacked and defeated by Soběslav's forces at the Battle of
Loděnice, he finally prevailed in a decisive victory outside the Prague city walls, in the area of present-day
Nové Město, on 27 January 1179. Soběslav was removed and died in exile the following year. The emperor now recognised Frederick as an
Imperial prince. The duke confirmed the drawing of the Bohemian-Austrian border and also maintained peace with his
Polish,
Meissen and
Hungarian neighbours. In 1184 he came to
Mainz to join the
Diet of Pentecost with a huge retinue to attend the knightly
accolade of the emperor's sons
Henry VI and
Frederick of Swabia. However, his reign remained overshadowed by the internal struggles of the Přemyslid dynasty: when he tried to assert the rule of his younger half-brother
Ottokar over Moravia, his former ally Prince Conrad of Znojmo turned against him and temporarily drove him out of Prague. Though re-instated by Barbarossa in 1182, Frederick had to face the elevation of Moravia to an Imperial
margraviate under Conrad's rule. The emperor also raised the
Prague bishop, Frederick's Přemyslid cousin
Henry Bretislaus, to
princely status, and thus divided the Bohemian lands into three parts all dependent on him. After years of wrangling, Duke Frederick, weakened by the internal struggles, was practically a puppet of the emperor. When Margrave Conrad was defeated by the forces of Frederick's half brother Ottokar in a bloody battle at
Loděnice, the Bohemian and Moravian Přemyslids finally met at
Knín in 1186. To settle the dispute, Conrad acknowledged Frederick's overlordship, while the duke confirmed Conrad's rights and his succession to the Bohemian throne. Frederick died in 1189, while he prepared to follow the emperor on the
Third Crusade. According to the Knín agreement, he was succeeded by Conrad (as Duke Conrad II) who once again united Bohemia and Moravia under his rule. ==Marriage and children==