[3] In his youth Sandanski was involved in the anti-Ottoman struggle, joining initially the Supreme Macedonian-Adrianople Committee (SMAC), but later switched to IMARO.
He supported the idea of a Balkan Federation, and Macedonia as an autonomous state within its framework, as an ultimate solution of the national problems in the area.
In 1879, after the suppression of the uprising, his family moved to Dupnitsa, in the recently established Principality of Bulgaria, where Sandanski received his elementary education.
From 1892 to 1894 he was subject to compulsory military service in the Bulgarian army, as part of the Thirteenth Regiment which was stationed in Kyustendil, and he was demobilized with the rank of corporal.
[8] Sandanski operated as an activist of Radoslavov's wing of the Liberal Party and shortly after it came to power in February 1899, he was appointed head of the Dupnitsa prison.
On 3 September 1901, a Protestant missionary named Ellen Stone along with her companions set out on horseback across the mountainous hinterlands of Macedonia and were ambushed by his detachment led by him and his friend Hristo Chernopeev.
"[14] The left-wing faction advocated the creation of a Balkan Federation (including Macedonia) with equality for all subjects and nationalities, as well as favouring the decentralisation of IMRO.
[9][15] Per Bulgarian historian and former IMARO member Hristo Silyanov, Sandanski's faction sentenced the right-wing leader Boris Sarafov to death in 1904.
[8] Sandanski created observation posts in his district order to watch for Turkish detachments, and the peasants were forced to warn or be killed.
French consul Guillois described Sandanski as "a ferocious man, bloodthirsty...who enjoys an absolute authority over all Bulgarian villages to the northeast of Salonika.
"[12] Sandanski justified the executions in an open letter to him and argued that the organisation had the right to ignore the law of the land and to punish as it saw fit.
[8] In 1905, the Rila Congress of the Internal Macedonian Revolutionary Organisation adopted the main ideas of the left-wing faction led by Sandanski.
However, the congress ended with the delegates deciding not to examine the cases of the leaders who could have violated the rules in order to preserve the organisation's unity.
In 1906, his faction controlled Serres and Strumica and for geographical reasons, it rarely fought against Serbs or Greeks but often against Ottoman troops.
Mihail Daev, who was a member of his committee, sent a letter to the right-wing faction in September 1907, where he asserted that as long as Sandanski was alive, there was no question of uniting the organisation again.
The letter was discovered by Todor Panitsa, an associate of Sandanski and on 10 October, the Serres committee sentenced Boris Sarafov, Ivan Garvanov and Mihail Daev to death.
[21] During the first days of Young Turk Revolution, the collaboration of the Macedonian leftists with the Ottoman activists was stated in a special Manifesto to all the nationalities of the Empire.
Sandanski called his compatriots to discard the "propaganda" of official Bulgaria in order to live together in a peaceful way with the Turkish people.
[25] Through his good relations with the Committee of Union and Progress (CUP), Sandanski contributed to the appointment of local administrators and the affairs of school education.
In the process of negotiations, Sandanski ensured the CUP that in his region he was responsible for all illegal actions and that it was unnecessary to disarm the population.
They came closest to achieving their goal in Thessaloniki, where Tane Nikolov managed to kill two of his comrades and heavily wounded Sandanski.
As a result, he was assassinated near the Rozhen Monastery on 22 April 1915 while travelling from Melnik to Nevrokop, by local right-wing IMARO faction activists.
[8] His famous words "To live means to struggle, the slave for freedom and the free man for perfection" are written on his grave.
[7] Sandanski criticised the politics of both Serbia and Bulgaria and accused them of being more interested in the enlargement of their states than in the freedom of the people in Macedonia.
[34] During World War II, the Macedonian Partisans named units after him and other figures, with whom the Communist Party of Yugoslavia and its regional leaders identified themselves with.
"[39] English historian Mercia MacDermott published a biographical book called For Freedom and Perfection: The Life of Yane Sandansky in 1988.
[30] MacDermott has described him as a Bulgarian revolutionary and whose wing, under the influence of socialist ideas, tried to solve the Macedonian Question by uniting all the Balkan peoples.
[41] Bulgarian president Georgi Parvanov placed a wreath on his monument in Melnik together with his Macedonian counterpart Branko Crvenkovski in March 2008.
[39] According to the Turkish professor of history Mehmet Hacısalihoğlu, who is interested in nation-building in the late Ottoman Empire,[43] it is very difficult to find a definitive answer to some questions regarding Sandanski's biography.
[47] Sandanski Point on the E coast of Ioannes Paulus II Peninsula, Livingston Island, Antarctica, was named after him by the Bulgarian Antarctic Expedition.