Waltari was born in Helsinki on 19 September 1908. His parents were Toimi Waltari and Olga Johansson; Toimi was a Lutheran pastor once, teaching religion in Porvoo, and Olga one of his pupils. A scandal caused by their relationship had forced them to move to Tampere and the two married each other on 18 November 1906. At the age of five Mika Waltari suddenly lost his father to illness on 5 July 1914, and the 25-year old Olga Waltari was left, with crucial help from Toimi's brother Toivo, to support her three children: Samuli (7 years), Mika (5 years) and Erkki (6 months). As a boy, he witnessed the Finnish Civil War, during which his White-sided family fled to the home of his mother's aunt at Laukkoski in Pornainen, near Porvoo, which was relatively peaceful and where the Whites were predominant.