Patriarch Neofit, the leader of the Bulgarian Orthodox church, died on Wednesday evening at the age of 78, the main secretary of the church council said.
Patriarch Neofit died of multiple organ failure in The Military Medical Academy of Sofia after a long illness, said Bishop Gerasim.
The head of the church had been receiving treatment there for a lung disease since the end of November 2023.
Neofit had been elected as head of the Bulgarian Orthodox Church in February 2013 and was also Bishop of the capital Sofia.
Neofit was born on October 15, 1945 in the Bulgarian capital and became Metropolitan Bishop of Ruse in 2004. His birth name was Simeon Nikolov Dimitrov.
A church council is to elect Neofit's successor within four months. There was initially no clear favourite.
The majority of Bulgaria's population is Christian Orthodox, with Catholics making up only around 1% of the population. Around 10% of the Bulgarian population are ethnic Turks, traditionally moderate Muslims.