The young Republic of Latvia felt more and more threatened since the begin of the World War II, and for good reason. They don't know, but in the secret Molotov-Ribbentrop Pact the Soviet Union got the Baltic States promised by Nazi Germany. As a consequence, the Soviet Union forced Latvia in early October 1939 to sign a "mutual assistance pact" with them - which allowed the Soviets to create Military bases in Latvia. The fact that both sides had a non-aggression pact with Germany didn't help them. On June 11th in 1940, they received an ultimatum; on the next day, the country was occupied.