Step 1: Understanding the historical context.
The landmass referred to here is India, which was freed from British colonial rule in 1947. India was partitioned into two independent countries: India and Pakistan.
Step 2: The date of independence.
India was officially declared independent on August 15, 1947, after a long struggle for independence led by various freedom fighters.
Step 3: Conclusion.
Thus, the landmass of India was freed to separate into countries on August 15, 1947.
Final Answer: \[ \boxed{\text{The landmass of India was freed to separate into countries on August 15, 1947.}} \]