Complex sentence: On 7 April 1946, the Königsberg Oblast (later renamed Kaliningrad Oblast) was founded that included the Memel Territory and becomes a new subject of the Russian Soviet Federated Socialist Republic.
Split into simpler sentences: On 7 April 1946, the Königsberg Oblast (later renamed Kaliningrad Oblast) was founded. It included the Memel Territory and became a new subject of the Russian Soviet Federated Socialist Republic.