Konrad Viktor Zilliacus (18 December 1855 in Helsinki – 19 June 1924 in Helsinki) was a Finnish independence activist involved in the Grafton Affair in 1905.
Zilliacus was born in Finland, then part of the Russian Empire. He studied law and then became a newspaper reporter, in which capacity he travelled the world, living for a period in Costa Rica, then in Chicago. He lived from 1894-1896 in Japan - when his son Konni Zilliacus was born in Kobe - followed by Egypt and Paris. He returned to Finland in 1898, and submitted a petition to Tsar Nicholas II in 1899 demanding a constitution. He subsequently relocated to Stockholm in Sweden in 1900, where he began to publish a newspaper Fria Ord ("Free Speech") which supported independence for Finland.
As one of the early leaders of the Finnish independence movement, he cultivated relations with the Russian revolutionary movement, and smuggled his newspaper and other revolutionary literature from Sweden to Finland on his yacht, as well as weapons. In February 1904, he met with Japanese military attaché and spymaster, Colonel Akashi Motojirō, who provided large sums of money to assist him in developing subversive activities in an attempt to create domestic political instability during the Russo-Japanese War. Zilliacus met with Polish independence activist Roman Dmowski and Russian revolutionary leader Georgii Plekhanov as well as other dissidents. With Japanese assistance, Zilliacus organized a conference of Russian revolutionary organizations in Paris in September 1904, which agreed upon a program of legal and illegal means to replace the current autocracy with a democratic government.
Following the abortive uprising in January 1905, he organized a second conference in Geneva in April 1905, with the participation of eleven revolutionary organizations. With Japanese financing, the conference purchased the steamer SS John Grafton and a large quantity of arms, which they unsuccessfully attempted to smuggle into Russia on September 8, 1905.
Following the independence of Finland, Zilliacus moved back to Helsinki in 1906; however, once his connections with the Japanese became public, he was forced to the United Kingdom with his family in 1909. His son, Konni Zilliacus was a Labour Party Member of Parliament of the United Kingdom for Gateshead and expert on British foreign policy.
Zillacus returned to Finland in 1918, and died in a nursing home in Helsinki. In his final days, he wrote his memoirs of his underground activities, as well as a cookbook.