Until 1926 the Imperial Cricket Conference, founded in 1909, had only three full members: England, Australia and South Africa. The expansion of the 1920s was driven partly by Arthur Gilligan's tour of India and West Indies recommendations, partly by the West Indies' competitive 1923 tour of England, and partly by the New Zealand tour of England in 1927 that produced strong county results.
The May 1926 ICC meeting at Lord's admitted the West Indies, India and New Zealand to associate membership and effectively granted Test status to the West Indies. The first West Indian Test followed at Lord's in June 1928. India was admitted to full membership at the May 1929 meeting (delayed because the BCCI was only formed in December 1928). New Zealand was also admitted at the May 1929 meeting; the first New Zealand Test followed in January 1930 at Christchurch.
The expansion increased the number of Test nations from three to six and roughly doubled the volume of Test cricket played per year. The structural consequence — more Test cricket, more national administrations, more uneven standards in early years — would dominate the cricket of the 1930s and 1940s.