The man whose writings and friendship influenced catherine ii of russia, frederick ii of prussia, and joseph ii holy roman emperor was: aristotle peter iii plato voltaire

Aristotle Peter III  is the man whose writings were influenced.

Explanation:

Fredrick was remembered as being the best father of the militarism during the Prussian militarism. However, the location of Prussia was near the borderland. There were vast empires that had to go for the war on frequent occasions. But this did not prevent Fredrick from unifying the nation. He yielded a highly-trained army who offered public education to other citizens

His admired had high ambitions on the continent, and it is through his efforts that Napoleon made efforts and visited him in his tomb after he had defeated Prussia.

i think the answer is a and i hope this ; ))