"The success of the Unification is due to the combination of factors that are very rare and then not repeated in Bulgarian history. On the one hand, there were people who still remembered their revolutionary years, like Zahari Stoyanov. There are military men who participated in the Serbian-Turkish war (1876) and then in the Russo-Turkish war (1877-78). There is a rather determined statesman like Stefan Stambolov. There is a unique combination of external political factors in which the main countries that have an interest in the Balkans have secretly agreed that they will not interfere if Bulgaria and Eastern Rumelia are united as long as the unrest does not transfer to Macedonia," the historian says.

Professor Ilchev believes that the members of the Unification Committee led by Zahari Stoyanov were not aware of this secret agreement between the Great Powers and literally risked their lives.

"Furthermore, don't forget that the preparation for the Unification was practically a month and a half - two at the most. These were the summer months when 70 percent of the population of both Eastern Rumelia and the Principality were peasants and they were busy, working to make a living. It's not the most convenient months to do a revolutionary organization. So it was really an adventure," emphasizes the professor.

Without the consent of the Bulgarian prince Alexander I of Battenberg, the Unification would also be doomed to failure. When the envoys of the committee went to the prince in Shumen during the military exercises and offered him to support the action, the ruler said that he bet his head and crown for the unification of the country.

"There is an underestimation of Prince Alexander I in Bulgarian historiography. Imagine: a 24-25-year-old man comes to Bulgaria to rule a country whose language he does not know. To rule a country for which he has no idea what it is like, regardless of having spent a few months during the Russo-Turkish war at the headquarters of the Russian army. And this man, within the span of 5-6 years allotted to him, actually developed a lot. At first, he made gross mistakes, such as establishing the regime of powers. Then he woke up to the reality and started behaving like a constitutional ruler. I personally think that if he had stayed on the Bulgarian throne for a longer time, the history of Bulgaria would have developed differently," the researcher claims.

The success of the Unification was protected in the subsequent Bulgarian-Serbian war in 1885, but it posed very high challenges to the Bulgarian politicians of the late 19th and early 20th centuries. They adhered to something that Prof. Ivan Ilchev describes to his students as “the unionist syndrome”.

"Every year on September 6, we talk about how great this date is, and it is a great date. But the Unification has, apart from all its positive consequences, also negative consequences, not for the state of Bulgaria as such, but in the minds of politicians, of those who rule it. The Unification misleads the Bulgarian politicians that they can go to Macedonia. It is interesting that they do not talk about Thrace at all. They think that the same things should be done in Macedonia as in Eastern Rumelia. They forget that in Eastern Rumelia 70 per cent of the population were Christians, while in Macedonia, according to the most optimistic Bulgarian statistics, Bulgarians were 54-55% the "Macedonian salad" dish appears - mixed vegetables, all kinds of vegetables," recalls Ilchev.

Bulgarian politicians are starting to talk about the autonomy of Macedonia in the hope of repeating the scenario with the accession of the autonomous Eastern Rumelia. But none of Bulgaria's neighbors in the Balkans at that time, none of the Great Powers in Europe, put into the concept of "autonomy" the same meaning that was put into Sofia, emphasizes the researcher. Bulgaria's neighbours are startled by the country's rapid territorial expansion only 6 years after its liberation. Therefore, they are naturally against the idea of the young country to seek rapid national unification. The price of this unionist syndrome was paid in the Balkan Wars and the First World War. That is why the professor urges, when we read the lessons of history, even the most successful ones, to always act with a little sense of humor, to to look under the glaze for the purely human dimensions of the past, while also thinking about the missed alternatives.