The split of Congress at Surat session continued till 1916. Tilak and Besant made efforts to reunite Moderates and Extremists into the congress. Ambika Charan Majumdar presided over the congress session of Lucknow in 1916. This session was important for two reasons :
(1). The Extremists rejoined Congress.
(2). Congress and Muslim League formed a pact.
At the Lucknow session Congress and Muslim League signed a pact to cooperate each other on the basis of common programme in political field, which is known as Congress-League Pact.
Tilak and Besant played leading role in Congress-League pact. This pact was opposed by Madan Mohan Malviya because Congress accepted the demand of 'separate electoral college' by Muslim League. It was a great achievement for Muslim League.
With the discontinuation of Non Cooperation movement in 1922, the Lucknow pact ended.
After the Surat split, Congress once again divided due to disagreement over the Montague declaration. The liberals under S. N. Bannerjee welcomed Montague declaration whereas Nationalist opposed it. At Surat session, liberals had expelled extremist from Congress but this time liberals left Congress to support government.
In 1918, the Liberals founded National Liberal League under the leadership of S N Bannerjee and it latter came to be known as National Liberal federation. Its other members were : Srinivas Sashtri, Tej Bahadur Sapru and Bipin Chandra Pal. Liberals referred Montague Chelmsford reform as Magna Carta of India.