Most of the life of Petko Kiryakov was not unveiled by historians but by the prominent Bulgarian writer Nikolai Haitov, who wrote a novel and a script which was turned into a TV series, which became a favourite of most Bulgarians.
Nikolai was uniformed of Mr Kiryakov
It mentions that he wrote of Kiryakov and we know about his life from him
( z1 uniform :ARG1 ( z2 person :name ( z3 name :op "Nikolai" ) ) :ARG2 ( z4 person :name ( z5 name :op "Mr" :op "Kiryakov" ) ) )