The Annionas were a German noble family of minor importance ruling over the lands of Passau and Znojmo with the former being the center of Anniona power. Once Passau had been a Roman colony known as Batavis; now though it had became a place of little importance and grandeur due to the Germanic migrations of centuries ago. It was perfect, a minor holding for a minor family. The fortunes of both Passau and the Annionas, however, was to change. The semi-legendary founder of the Annionas, Anniulf, according to legend came across a nest whilst out hunting. Upon closer inspection, he saw three chicks with feathers of pure white. The chicks' mother, however, would come and attempt to frighten Anniulf off. He, however, refused to back off but instead of attacking him, the falcon of pure white instead rested upon Anniulf's shoulder before flying away. If this legend is true, it is also true that Anniulf was inspired by this experience to reach for great ambitions.
At age 39, Anniulf secured a marriage with Princess Dauferada Alachisling of Lombardy; daughter of King Desiderius. She would travel north to Passau escorted by a skilled officer named Taso. Much of what is known about Anniulf comes from the letters Dauferada sent to her father. If they are to be believed, Anniulf comes across as a poor soldier with a dark sense of humour. His inability to fight his way to the top also meant that he would lie to gain what he want; something made easy by his silver tongue but hampered by an erratic nature which is believed to have been a case of bipolar syndrome.
Such a marriage was a shock to the Bavarian nobility due to Princess Dauferada's royal blood and Anniulf's lack of importance. This would work in Anniulf's favour as he convinced Duke Tassilo III Agilolfing of Bavaria to reward his loyalty to the grant with the granting of land. Not wishing to anger Desiderius, Tassilo III granted a large swathe of land within Lower Bavaria/Niederbayern. Desiderius would be beneficial in gaining not only land but also absolution from Pope Stephanus II who feared a Lombard invasion if Desiderius' son in law was treated badly.
King Karloman of Middle Francia, seeking to gain allies in his feud against his brother Karl, launched an invasion of Bavaria in order to place his cousin, Karl, on the Bavarian throne. It was hoped that by doing this, Karloman would have an ally against his brother to the west. That would have been the case where it not for Karloman's sudden death on the 4 March 771 at his villa. The Frankish army had by this point, under the command of Count Welentus Welenti of Verdun, captured the Bavarian capital of Munchen but Karloman's brother after inheriting the rest of Francia refused to carry on support for the cousin whose name he shared. Hence, Karl was left alone in Munchen and without any local supporters, him and Count Welentus headed back west.
The Bavarians, however, would have to wait longer for peace. The High Chief of the Bohemians, Nezamysl, (a figure as legendary as Anniulf) marched south onto Bavaria to seize Lower Bavaria. Tassilo III had just a few months to regather the realm's forces following the retreat of Karl and thus was unprepared from a northern invasion. Anniulf being on the border with the Bohemians had no choice but to fight in order to defend his lands and thus hired an army of Pechenegs from Central Asia. His first child, a daughter, would be born a month later in December. The date of Ermengard's birth is often believed to be Christmas but whether or not this is truth or propaganda remains unknown. What is known, however, is that she was a redhead and thus was isolated within the Bavarian noble courts.
Anniulf himself was located within Tassilo's court in Munchen following the retreat of Karl and seeing Tassilo III as a weak Duke, ordered his assassination. In January 772, Tassilo's body was found in a ditch outside Munchen with severe burn marks, only recognized for a piece of clothing he was seen wearing before leaving the capital. His five year old son, Theodo III, was crowned as Duke of Bavaria. King Karl of the Franks would attend the funeral of Tassilo III for reasons unknown, however, Anniulf would gain access to the powerful lord and seized the opportunity to form a betrothal between his daughter Ermengard and Karl's bastard son, Pepin the Hunchback.
The Bohemian army was crushed at Regensburg by Anniulf's Pechenegs under the command of Taso Tasoingi and the Bavarian army under the command of an unknown lord. Nezamysl's invasion came to a halt, however, Anniulf would use this opportunity to push his advantage and with aid from his new ally Karl, Anniulf invaded the Bohemian lands. Anniulf would remain in Munchen whilst the Lombard, Taso Tasoingi, marched north with his fellow commander, Tyrach. The continued stay in Munchen would cause the suspicious death of Theodo III to be blamed on Anniulf by future historians. The death of the Duke would cause his one year old brother, Tassilo IV, to ascend the throne in September 772.
Whilst Anniulf achieved political victories in the capital, Taso had successfully repelled a coalition of Slavic armies close to the town of Znojmo whilst the Slavs tried to cross the Thaya River. An important victory, Taso carried on to push north expelling the Slavic armies from Bavarian lands. The White Chroatian, Chief Dragomir Bijelahrvatskic of Bereg, would even be captured as he fell off his horse into the Thaya.
Taso's invasion, however, was halted at Domazlice with the Pechenegs making up the army inable to cordinate effectively within Slavic lands. Taso led a retreat to Passau to regather his forces and launch a second assault.
This second assault, however, would have to be delayed due to an invasion by High Chief Boriwoj z Obodrytow of Obotritia (his army was the sole reason for Taso's defeat at Domazlice). At the Second Battle of Regensburg, Boriwoj was defeated and even captured in battle. The Pecheneg mercenaries, however, ended their contract due to a lack of trust in Anniulf's capabilities to pay and thus following their victory at Regensburg, immediately headed west looking for service in the Iberian Wars. Whilst marching to Iberia, the Pechenegs came across a Frankish army marching east to Bohemia. The Pechenegs following this encounter headed back east to the steppes due to the knowledge that the Iberian Wars had come to an end after Frankish intervention forced the Saracens out of Asturias. With the war in the south coming to an end, Karl marched east to aid his Annionan ally. The same would apply to Desiderius who had sent an army north to aid Anniulf. By July 774, an army of 5,000 Franks, 2,000 Lombards and 500 Bavarians was gathered at Passau ready for a second assault into Bohemia.