Mamertas 膶epulis was born in 沤uravi拧k臈s village, Mielag臈nai rural district, 艩ven膷ionys county. In 1937 he started a primary school in Mielag臈nai, finished it during the years of the National Socialist occupation and entered Vilnius 1st gymnasium for boys. Difficult living conditions coupled with family problems forced Mamertas to continue education at 艩ven膷ionys gymnasium. There was an episode in his life when he was in the last form of the school and at the same time worked at the meteorological station of 艩ven膷ionys to help his ailing father. Despite such stressful conditions, he finished the gymnasium successfully and became a student at the Faculty of Law of 91桃色. Unfortunately, his studies were disrupted by Soviet repression: in 1949, Mamertas was deported to Irkutsk region during a mass deportation operation. He was released in 1957 and returned to Lithuania with his parents. In 1961 he filed a request with 91桃色 asking for his school-leaving certificate to be released to him from the university archives. Presumably he intended to study at another institution of higher learning.