When the British left our country in August 1947, India was actually the British India and Indian India. The British India was consisting of 9 Governor's provinces, 5 chief commissioners provinces and some other tribal areas, Andaman Nicobar Islands etc. The Indian India consisted of some 562 Indian states including the major states such as Hyderabad, Kashmir, Mysore, Travancore, Baroda, etc. However, most of them were too small in size and too poor in resources. They all became independent and autocratic and resembled the medieval Europe. On 15 August 1947 all were technically "Sovereign".

The Indian independence act made them completely free to join either of the dominion or remain free. Except a few, which joined Pakistan, most of them decided to join India and this was unification of India in several centuries.

The accession to the Indian dominion started the new movement of territorial adjustments which included the integration and merger. Integration Involved joining of two or more states in one big administration unit such as Rajasthan and merger involved small state merging with their neighbor states such as Saraikella in Bihar.

This territorial readjustment brought the number of states under the Indian Union to 16 from the 600. The major political vision and statesmanship behind this movement was Sardar Vallabh Bhai Patel and he is also called the chief architect of Republic India.

• For the first time while explaining the meaning of the "Swaraj" mahatma Gandhi had indicated in 1922 that constitution of India would be drafted by the Indians.
  

  For the first time, the constitution for India was drafted by Nehru Committee in 1928. In the Lahore session of 1929, Congress adopted the Poorna Swarajya. In 1934, the demand for a constituent assembly was raised for the first time, which was later became an official demand in 1935.
  

  This demand was accepted in August 1940 offer by the British. On august 8, 1940, a statement was made by the by the Viceroy, Lord Linlithgow, on the expansion of the Governor-General's Executive Council and the establishment of a War Advisory Council. This offer also promised for giving full weight to minority opinion, recognizing the Indians to form their own constitution.
  

  Under the cabinet mission plan of 1946, elections were held for the first time for constituent Assembly.
  

• The Constitution of India was made by the constituent assembly and it was set up under the cabinet Mission plan on 16 May 1946.
  
• The members of the constituent assembly were elected by the Provincial assemblies by method of single transferable vote system of proportional representations.
  
• Total membership of the constituent assembly was 389, out of which 292 the representatives of the states were, 93 were representatives of princely states and 4 were from the chief commissioners provinces of Delhi, Ajmer-Mewar, Coorg and British Baluchistan.
  

  The elections for the 296 seats assigned to the British Indian provinces were completed by July-August 1946.
  

• Congress won 208 seats and Muslim league won 73 seats.
  

  After this election, the Muslim league refused to cooperate with the Congress. The political situation got worse and Hindu Muslim riots started. The Muslim league demanded for a separate Constituent assembly for Muslims in India.
  

• On June 3, 1947, Lord Mountbatten , the last British Governor General of India announced his plan of scrapping the Cabinet Mission plan and this later culminated in Indian Independence Act and separate nations India and Pakistan.
  
• The Indian Independence act was passed on July 18, 1947.
  

  Earlier it was declared that India will get its independence in June 1948, but this event led to an early independence on August 15, 1947.
  

• The Cabinet assembly which was elected for an undivided India met for the first time on June 9, 1946.
  
• It reassembled on 14 August 1947 as a sovereign body and successor to the British parliament's plenary authority and power in India.
  
• As a result of the partition, under the Mountbatten plan a separate constituent assembly was set up for Pakistan on June 3, 1947.
  
• The representatives of the members which were from the areas of the Pakistan ceased to be members of the Constituent assembly of India
  
• Fresh elections were held for west Punjab and east Bengal which were now in Pakistan.
  
• The membership of the Constituent assembly became 299 after this reorganization and it met on December 31, 1947.
  
• The Constituent assembly was the First parliament of Independent India.
  
• Dr. Sachchidananda Sinha was the first president (temporary Chairman of the Assembly) of the Constituent Assembly when it met on December 9, 1946.
  
• Dr. Rajendra Prasad then became the President of the Constituent Assembly, and who later become the first President of India.
  
• The Vice President of the Constituent Assembly was Professor Harendra Coomar Mookerjee, former Vice-Chancellor of Calcutta University and a prominent Christian from Bengal who also served as the Chairman of the Minorities Committee of the Constituent Assembly. He was appointed Governor of West Bengal after India became a republic.