Ilinden was a veteran unpolitical organization established in Sofia in 1921 with branches in a whole of Bulgaria.
[1] It was founded by leaders of the former Internal Macedonian Adrianople Revolutionary Organization, who did not participate into the new Internal Macedonian Revolutionary Organization (IMRO) founded by Todor Alexandrov after the First World War.
In 1924 Alexandrov several times spoke with Petar Atsev, then president of the organization, on the occasion of a growing communist propaganda among its members.
In 1924 Aleksandrov was killed, but as participants in the conspiracy against him were suspected the leaders of the Ilinden organization.
In the following years Ilinden organization was primarily engaged in cultural and educational activities.