Numerous attacks were carried out by IMRO against Yugoslav officials under his leadership, the most spectacular of which was the assassination of Alexander I of Yugoslavia, in collaboration with Croatian Ustaše.

[3] He actively cooperated with revanchist powers, such as Mussolini's Fascist Italy, Admiral Horthy's Hungary and Hitler's Nazi Germany.

[9] During the Cold War, Mihaylov lived in Italy while the emigrant Macedonian Patriotic Organization in the US and Canada worked under his guidance on the old IMRO's goal of an independent Macedonia.

This was acknowledged by a CIA report from 1953, which dubbed the MPO as "the US branch of the IMRO" and asserted that it acted as a money-raising organ to support Mihaylov's activity.

[16] Ivan Mihaylov was born on 26 August 1896 in the village of Novo Selo (today a quarter of Štip, North Macedonia), in the Kosovo vilayet of the Ottoman Empire.

On 31 August 1924, Todor Aleksandrov was assassinated in unclear circumstances and IMRO soon came under the control of Mihaylov, who had become a powerful figure in Bulgarian politics.

[17] Dimo Hadjidimov, Georgi Skrizhovski, Aleksandar Bujnov, Chudomir Kantardjiev and many others were killed in a series of consecutive murders all taking place in 1925.

The conflict grew into a leadership struggle and Mihaylov soon, in turn, ordered the assassination in 1928 of a rival leader of the older group, General Aleksandar Protogerov, which sparked a fratricidal war between "Mihaylovists" and "Protogerovists".

The most spectacular of these was the assassination of King Alexander I of Yugoslavia and the French Foreign Minister Louis Barthou in Marseille in 1934, in collaboration with Ante Pavelić.

In 1934, Mihaylov fled to Turkey and ordered his supporters not to resist the Bulgarian army and to accept the disarmament peacefully, potentially avoiding a civil war or foreign invasion.

As a result of this, IMRO had built an extensive network in Pirin Macedonia and in the other parts of Bulgarian territory, which was used to provide financing for the organization and an operational base from which the offensives into Yugoslavia and Greece were conducted.

While in exile, IMRO was kept alive by members in various countries worldwide, but ceased to be an active force in Macedonia except for brief moments during the Second World War.

After 1934, Mihaylov lived in Turkey, Poland and Hungary and finally settled in the Croatian capital Zagreb, which at that time was part of the Independent State of Croatia, a fascist puppet-state.

It was also anticipated that the IMRO volunteers would form the core of the armed forces of a future Independent Macedonia in addition to providing administration and education in the Florina, Kastoria and Edessa districts.

[26][non-primary source needed] Gradually Ivan Mihaylov was established as a legal political figure and author of the ideology of the Bulgarian national liberation movement in Macedonia.

This fact allowed for a close political alliance between Ivan Mihaylov and the Macedonian Patriotic Organization in the United States, Canada and Australia in the late 1940s.

In order to provide a basis for the Bulgarian emigrant movement and create a historical record, Ivan Mihaylov started writing his memoirs from the 1950s to the 1970s, which the MPO's Central Committee published in four large volumes.

[27] After the change of Bulgarian policy toward the Macedonian question in the late 1950s, Mihaylov was largely forgotten about and according to some sources even in the 1970s and 1980s the Committee for State Security supported his pro-Bulgarian and anti-Macedonistic political activity.

[29][30] The Constitutional court of the Republic of Macedonia banned the Radko Association, a pro-Bulgarian organization bearing the name of Ivan Mihaylov as separatist.

[33] There are different political opinions about Mihaylov's activity in Bulgaria, but scholars agree that he was a defender of the statement about the strong Bulgarian character of the Slav-speaking population in the region of Macedonia.

[34] He was a follower of the idea about an independent United Macedonian multiethnic state with a prevailing ethnic Bulgarian element, something as "Switzerland on the Balkans".

He believed that the Macedonians are part of the Bulgarian nation and the founders of IMRO were people who accepted the San Stefano Bulgaria.