Monjé, a pipefitter by profession in the port of Rotterdam, was co-founder of both the Socialist Party and its direct predecessor, the Communist Unity Movement of the Netherlands (Marxist–Leninist) (KEN-ML).

[1] Monjé was expelled from the Communist Party of the Netherlands (CPN) together with his kameraad Nico Schrevel in 1966 because of overt sympathy for Mao.

From 1967, the course to influence the CPN was abandoned and attention was directed towards the formation of a distinct political party.

[4] Before the conflict could be resolved in the party, he fell seriously ill. Daan Monjé died in October 1986 at the age of sixty.

His funeral at Hofwijk General Cemetery in Rotterdam was attended by hundreds of kameraden from the CPN, KEN and SP.