When did the Soviets develop their own Atomic Bomb?

The Soviets tested their first weapon in 1949. And they didn't invent it themselves; spies gave it to them; they were later found and executed.

They actually didn't steal it, it was created in 1947 under The Soviet weapons program under the leadership of physicist Igor Vasilievich Kurchatov, and then tested fr the frst time in 1949.