The mighty Kubrat, whose sons later founded five more Bulgarian state formations on the map of Europe, quickly made the name of the Bulgarians famous and turned them into a serious military-political force. 

In 635, the leader of the Bulgarian tribe of the Onogundurs, Khan Kubrat, created in the Azov and Black Sea steppes the great tribal union "Old Great Bulgaria". The country grew rapidly and became a serious military-political factor in the medieval world.

The beginning of the land that remained in history under the name of Old Great Bulgaria was set in 635. The Khan Kubrat, who had returned from Constantinople, was promoted by his uncle Organa as ruler of the Onogudurs. Together with his relative, Kubrat launched the offensive against the Avars, to reject the dependence of the Bulgarians on them.

After a series of heavy battles in the Black Sea steppes, during one of which Organa perished, Kubrat gained his independence. The new ruler of the Bulgarians quickly concluded a treaty with the Byzantine emperor Heraclius, with whom they were good friends from the time he spent in Constantinople. Kubrat took responsibility for defending the Eastern borders of the empire from potential enemies marching on Byzantium. In return, the emperor gave him the title of patrician and showered him with generous gifts. According to chroniclers, this title is not accidental. It is believed that Kubrat converted to Christianity in Constantinople, and later many members of his own family and relatives adopted the new faith. This explains the good relations he maintained with the imperial family, including the support he provided after the death of Heraclius to his wife Martina and his sons.

Khan Kubrat showed religious tolerance towards the peoples entering the borders of his state, while at the same time being a relentless opponent and a fierce warrior. The Ashina clan, with which the Khazar tribe was related, was their arch enemy and blood rival. Kubrat fought bitterly against them, and only after his death did the Khazars succeed in gaining supremacy and conquering large parts of Greater Bulgaria. The latter was in fact a natural process resulting from the migration of Kubrat's sons. Contemporary analysis shows that the main reason for it was the drive to discover new fertile lands, where Bulgarians could settle permanently and abandon their semi-nomadic way of life. Subsequently, two of them, Danubian Bulgaria, within whose borders live contemporary Bulgarians, and the Volga-Kama Bulgaria, established themselves and reached even greater prosperity. However, what is extremely important to know about Old Great Bulgaria is that it marks the beginning and the process of uniting the consciousness of Bulgarians as one. Khan Kubrat pushed his scattered and often feuding countrymen to form their national self-consciousness.

Initially, the Proto-Bulgarian tribal union under Kubrat emerged on the territory that was subordinated to the Western Turkic Khaganate. The Khan contested and rejected their domination in 631. As the westernmost borders of this Khaganate reached the Caucasus, the Black Sea, the Sea of Azov and the Don River, it is where the the "Old Great Bulgaria" was formed and created. It was the main core around which other tribes were then united, forming the Proto-Bulgarian tribal union during its zenith.

 After the treaty of peace with Byzantium in 635 and the stabilisation of the situation in the east, Kubrat brought other tribes under his influence. It is no coincidence that Theophanes mentions that around the Sea of Azov and Phanagoria, besides Jews, lived "a great number of people". Undoubtedly, there were Magyar (Hungarian) tribes among them, for which there is a large amount of written, linguistic and archeological accounts. It was quite natural in this situation for the expansion of "Old Great Bulgaria" to take place in the lands west of the Don River, where the Proto-Bulgarian tribe of the Kotragi (Kutriguri) lived.

The very fact that the Kotragi were listed as subordinates to Kubrat gives grounds to claim that the Proto-Bulgarian tribal alliance extended west of the Don River. This is confirmed by the fact that after the disintegration of the tribal alliance following the death of Khan Kubrat, one of his sons (Khan Kotrag) settled permanently in the area between the Dnieper and the Don, lands that came under the rule of Old Great Bulgaria.

The borders of the Proto-Bulgarian tribal union led by Khan Kubrat can be enclosed as follows: to the east, the lower reaches of the Volga River and from the Caspian Sea to the Caucasus. To the south, the Caucasus Mountains, the Black Sea, the Sea of Azov (excluding Crimea) to the Karkinitsky Bay. The western border ran along the Dnieper River, and in some sections it reached the Bug River. The northern border reached the Ergeni mounts (this elevation is referred to as the Horse Mountains or the Bulgarian Mountains) and the bend of the Don River, as the direct neighbours of the Proto-Bulgarians there were the tribes of the Antes.

The capital and main city of the Proto-Bulgarian tribal union was called Phanagoria. This old settlement emerged around the VIth century BC on the shores of the Bay of Taman. Later in the IVth century AD, the city was sacked by the Huns and Goths. In the Vth and VIth century, the city gradually began to recover and even became the center of the Diocese of Phanagoria. Its rise and recovery was due to the successful policy of Kubrat and the good maritime trade contacts that the Bulgarian ruler maintained and carried out, through the port of Phanagoria.

The history of the Proto-Bulgarian tribal union led by Khan Kubrat is reflected in a unique way in the oldest Bulgarian chronicle, "The Nominalia of the Bulgarian Khans".

Kubrat ruled Old Great Bulgaria in the period 635-650. An authoritative statesman, endowed with exceptional military talent and wisdom, the Bulgarian ruler not only managed to unite the scattered Bulgarians, but left us his wisdom and covenant, with which all Bulgarian children are inspired today. Khan Kubrat's words echo through time to show us and make us remember that only together, with united efforts, the Bulgarians are able to perform great deeds.

In the Historical Park, visitors and guests can purchase the comic book "Khan Kubrat: the Testament of the Bulgarians", which presents in a fascinating way part of the great history of Bulgaria. Distributed free of charge to all third-graders in Bulgarian schools by the Vazdigane (“elevation”) Foundation, it aims at preserving the proud and ancient Bulgarian spirit, to nourish the strength of today's children. Having received a piece of the wisdom handed down to them over the centuries by the great Bulgarian statesman, they will glorify the name of their homeland all over the world with honour and dignity.