How the six faiths spread

How to read the map

• Regions are built from today's states and provinces as building blocks, chosen from each source's description, and labeled with the names the sources use. They show where a faith was present, not where every person followed it.
• Accounts that reach back before each faith's community are not mapped, for any faith. The History pages tell them.
• A blank area means no source has been found yet for that faith there at that step. The data page lists the places still waiting for a source.
• Where a region or event gives a tradition's own account, it cites that tradition's own sources, such as the Orthodox Union, the Orthodox Church in America, Access to Insight's Theravada chronology, the Himalayan Academy, The Church of Jesus Christ of Latter-day Saints, and the hadith collections Sahih al-Bukhari and al-Kafi, beside the scholars.
• From 1950 the dots use the World Religion Project's figures to 2000 and Pew Research Center's for 2010 and 2020. The two sources count in different ways, so a change from 2000 to 2010 can come from the change of source as well as from a change in the world.
• Both sources give one figure for each country. Within a country, this map spreads each faith's dots by where everyone in the country lives today, from Kontur's population map of 2023, not by where that faith's followers live. So where a faith's followers live mostly in one part of a country, its dots are spread over the whole country, and a region drawn to 1900 can look as if it moved at 1950. For the countries and steps listed on the data page, a census or survey near the step gives religion by region, and its figures first share each faith's dots among those regions.
• Hatched places have no figures at that step. The World Religion Project counts independent states, so in the early steps it has no figures for places that were then colonies, including much of Africa and parts of the Middle East and Asia, and each faith's total grows from step to step partly because new states enter the count. Pew covers countries and territories of at least 100,000 people.
• Each source counts in its own way, and counting a person in a group is a counting rule, not a ruling on who belongs to a faith. Pew counts people who identify with a religion, mostly from censuses and surveys that ask. The World Religion Project combines census-based figures and other estimates, relying mostly on secondary data for past years; in Cuba, Haiti, and Japan it counts many people in two religions. For Buddhism, Pew notes that its count works less well in East Asia, where Buddhism is closely mixed with folk religion. For Christianity, Pew notes that many Christians in China worship in unauthorized venues, such as house churches, and may be reluctant to reveal their identity. For Judaism, counts depend on how Jewishness is defined: outside Israel, Pew generally counts people who give Judaism as their religion, so in the United States it leaves out Jews of no religion, and in Israel it uses the government's population register.
• The Latter-day Saint layer has no counts yet. Neither source counts Latter-day Saints separately. Pew counts everyone who identifies as Christian as Christian, and has named Latter-day Saints among the Christian groups it counts; that is a counting rule, not a ruling on whether they are Christians. The Latter-day Saint church's own membership figures by country are not shown yet; the Latter-day Saints Today page gives its latest figures.
• In the Largest group view, the largest group is not always a majority. In the World Religion Project's figures, used to 2000, the counts of people with no religion and of other religions are partly leftover categories from its sources, so a country's color can change between steps when only the estimate changes.
• The data page lists every region and event with its sources, and the follower counts, in text.