John III's death marked a moment of deep change into byzantine Imperial politics, both inside and outside the Rhomania's borders. Manuel and Zoe quickly seized the Imperial
regalia, with the support of the filo-Palaiologan elites, and undertook strict measures in order for the transition of power to take place as smoothly as possible. They, under the advise of Manuel's uncle Nikephoros, the all-powerful
Logothethes, even went as far as confining the only perceived rival claimant, the blind Simeon Kontostephanos, in his palace, so that he could neither be strumentalized by any potential enemies nor advance a claim onto the throne. In a way, Zoe and Manuel's precautions were unjustified, as Kontostephanos had already sworn an oath of fealty to the soon to be crowned Imperial couple, and could have never boasted a serious claim because of his phisical menomation; reconciliation would follow, but the event left a major strain on the relationship between Kontostephanos and the Palaiologoi elites, which was to be turbolent, at best.
While the new rulers' relationship with some circles of the aristocracy was uneasy, that between Empress Zoe Porphyrogenneta Komnena-Doukaina and her husband and co-Emperor Manuel proved to be a functional one. Their first daughter, Maria
Porphyrogenneta, was born in 1202 AD; four years later, the Empress gave birth to a male heir, Alexios
Porphyrogennetos, who was in turn followed by two other males, Nikephoros - in 1210 AD - and Andronikos, in 1213 AD. Their relationship was also proficient in many other aspects, as the two ruled jointly without major dissent despite the changes Manuel introduced in the ruling of the
Basileia.
With Manuel II Komneno-Palaiologos' accession to the throne, in fact, the old Komnenian practice of favouring kinship ties over others in regard to the management of the State reached a new apex. Not only was the sexagenarian Nikephoros Palaiologos confirmed in his title of
Megas Logothethes, but many other relatives of the young Manuel were entrusted with senior roles in Imperial administration and military, including his own eldest brother, thirty-four years old Isaac Stephanos, who was made
Megas Domestikos and therefore the most influential man in the Empire's military. Thus, it is evident how the transition of power from the last Komnenoi to the early Palaiologoi resulted in a change in Imperial administration, monopolized by affiliates and relatives of the new Imperial House, with the notable exception of the newly entitled
Megas Doux Alexios Kantakouzenos, who was still tied to the old administration.
All these factors contributed to the impression that, after the hardships of the anarchy which followed Manuel I Komnenos' demise, and thanks to John III's intense military activity, the Empire was to live a new golden age of relative tranquility, power and stability. However, this impression couldn't hava been more wrong: conflicts were about to soon come, as the Danubian frontier was about to be threatened by the Empire's northern neighbour, the Hungarians.
With the deaths of his uncle Ladislaus II and his brother Stephen III, Kowacz Arpàd had seized the Hungarian Crown in 1200 AD, virtually without any opposition. The humiliating experience of Roman captivity in 1189-1191 and the trauma of losing his father, Geza II, in battle against John III at Scutari, had left a permanent mark on Kowacz's personality and made it so that his tenure as King of Hungary was clearly an anti-byzantine one. Ever since his accession, he began to plot with Serbian magnates for an uprise against their Roman overlords; with news of John's death, and the accession of the young and inexperienced Imperial couple, Kowacz saw the chance to take his revenge against the hated
Rhomaioi and re-establish Hungary as a major power in the Balkan area.
Hostilities with the Hungarians openly broke out in 1204 AD, while celebrations were being held in Constantinople for the birth of Maria Palaiologina, Manuel and Zoe's first born daughter: Miroslav Zavidovic Frangepan, Conestable of Hungary and Count of Baranya and Pècs, crossed the Danube at the head of a rather sizeable host of 19.000 men, while the Serbian magnates rose up in revolt against their Roman overlords and overthrew the Basileus' representatives in the region. In short time, the whole of the Basileia's european frontier was on fire, with the Hungarian Conestable in Northern Boulgaria, Serbia in revolt, and Roman enclaves on the Adriatic threatened by Kowacz's Dalmatian and Croatian subjects.
Roman reaction was coordinated by the Basileus' paternal uncle Andronikos Makrodoukas Palaiologos, who ruled over the theme of Boulgaria and Paristriou and thus the very sector threatened by Frangepan. Makrodoukas marched his army towards Sirmium, where he engaged the Hungarian Conestable and was soundly defeated: casualties were high, and forced Makrodoukas to whitdraw in all haste towards Thrake and Makedonia, where he could replenish his forces.
Makrodoukas' whitdrawal, however, provoked the collapse of Roman positions in Boulgaria, allowing Frangepan to advance as far as Sardika, the region's capital, which he laid siege to. The event prompted caused great sensation in the Queen of Cities, and prompted Manuel and Zoe to undertake great efforts to restabilize the situation, which seriously threatened to undo everything that had been achieved in Europe during John III's reign with sweat, tears and blood.