[1] Baháʼu'lláh, ʻAbdu'l-Bahá, and Shoghi Effendi stated how Spiritual Assemblies should be elected by the Baháʼís, defined their nature and purposes, and described in considerable detail how they should function.
In 1899 the Baháʼís of Chicago elected a local council based on their awareness of the provisions of the Kitáb-i-Aqdas (which was circulated in provisional English translation as a typescript as early as 1900).
[12] In the period of 1900 - 1911, consultative bodies are known to have existed in Kenosha, Wisconsin, Boston, Massachusetts, Washington, D.C., Spokane, Washington, northern Hudson County, New Jersey, the greater San Francisco area, California, in the United States; and in Bombay, British Raj India; Cairo, Khedivate of Egypt; Acre, Ottoman Syria; Baku, Tbilisi, Ashgabat and Samarqand in the Russian Empire; and Mashhad, Abadih, Qazvin, and Tabriz, Persia.
[13] Because efforts to organize local Baháʼí consultative bodies remained informal, few additional ones had formed by 1921 (notable exceptions being Cleveland, Ohio, and London), and some of the ones in the United States had lapsed.
Upon assuming the Guardianship of the Baháʼí Faith, Shoghi Effendi read ʻAbdu'l-Bahá's Will and Testament and made establishment of local spiritual assemblies an early priority.
The result was a rapid proliferation of local Spiritual Assemblies; a 1928 list had the following: Australia, 6; Brazil, 1; Burma, 3; Canada, 2; China, 1; Egypt, 1; England, 4; France, 1; India, 4; Japan, 1; Korea, 1; Lebanon, 1; New Zealand, 1; Palestine, 1; Iran, 5; Russia, 1; South Africa, 1; Switzerland, 1; Syria, 1; Turkey, 1; and the United States, 47, for a total of 85 local Spiritual Assemblies worldwide.
National Spiritual Assemblies are first mentioned in ʻAbdu'l-Bahá's Will and Testament, but the fact that they would be established circulated for years before the contents of the Will became publicly available in early 1922.
In 1909, Hippolyte Dreyfus [fr] wrote extensively about the role of the national House of Justice (as it would have been known then) in his The Universal Religion: Bahaism, Its Rise and Social Import.
The 1928 issue of The Baháʼí World listed nine National Spiritual Assemblies: Persia (Iran); the United States and Canada; Germany; Great Britain and Ireland; India and Burma; Egypt; Turkistan; Caucasus; and Iraq.
The members of the National Spiritual Assemblies collectively serve as the electoral college for electing the Universal House of Justice, the supreme governing body of the Baháʼí Faith, which was first formed in 1963.