Prefer primary sources.
We begin with Istat, Roma Capitale, constitutional text, named research methods, and original institutional reporting.
Research & sources
Evidence should clarify the mission.
Not decorate it.
We publish the sources behind our major factual claims, explain what the numbers measure, and name important limitations. The goal is not to make uncertainty disappear, but to be honest about it.
Our method
Four rules for using evidence.
Mission research serves people best when it is careful enough to resist both exaggeration and false precision.
Keep the denominator visible.
A percentage of citizens, foreign residents, adults, attenders, or survey respondents describes different populations.
Separate data from interpretation.
Statistics describe patterns. The missionary implications are our interpretation, and we label them accordingly.
Say when estimates disagree.
Disagreement is often evidence of different definitions or methods, not necessarily error or bad faith.
Definitions matter
Words we do not use interchangeably.
Christian
A broad religious identity that may include Catholic, Orthodox, Protestant, and other traditions. Survey identification does not necessarily indicate belief or practice.
Catholic
A specific Christian tradition and institutional identity. Catholic self-identification, sacramental participation, and Mass attendance are separate measures; none should be inferred from a broad “Christian” label or an all-religions attendance question.
Protestant
A historical and sociological family that includes multiple traditions. Some datasets use this broader category where ministry organizations might use “evangelical.”
Evangelical
A theological identity centered on the authority of Scripture, the gospel of Christ, personal conversion, and active witness. Not every Protestant body or respondent uses the term the same way.
Member / adherent / attender
A formal member, a person associated with a church, and a person present at worship are different units. Church estimates may count one or several of these.
Foreign citizen / foreign-born
Citizenship and birthplace are different. A naturalized Italian may be foreign-born; a child born in Italy may remain a foreign citizen under Italian law.
“Unreached”
A mission-research category usually based on population-level access and Christian presence. It must not be assigned to an individual from nationality alone, and different databases set different thresholds.
What we can say confidently
Direction is clearer than precision.
Reported attendance at places of worship has declined substantially; younger adults attend less; Protestant and evangelical Christians remain a small minority; Rome is internationally connected and religiously diverse.
The Istat attendance series cannot tell us how many respondents are Catholic, evangelical, Orthodox, Muslim, or from another tradition. We are also less confident in any single exact count of “evangelicals,” the religious composition of Rome’s migrant communities, or a claim that nationality predicts gospel access. Those questions depend on definitions, incomplete reporting, survey design, and modeled estimates.
When a clean statistic would overstate the evidence, we prefer a range, a rounded figure, or a plain explanation of uncertainty.
Source library
Read the evidence directly.
Publication dates describe the source or estimate, not necessarily the date the webpage was last updated. Links are external.
Religious practice and secularization
Thirty Years of Daily LifeIstat · 2026
National trend in attendance at any place of worship, 1995–2023. It is an all-religions measure, not a Catholic Mass or evangelical church census.
Being Christian in Western EuropePew Research Center · 2018Survey evidence on Christian identity, practice, belief, and non-practicing Christianity. Useful but older than Istat’s attendance series.
Religious Switching in 36 CountriesPew Research Center · 2025Measures current affiliation against childhood religion; does not measure conversion within Christianity.
Evangelical and Protestant presence
Dimensions of Religious Pluralism in ItalyCESNUR · 2023 estimates
Estimates Italian-citizen religious minorities and models noncitizen affiliation. Definitions and component totals are published.
29th Report on MigrationFondazione ISMU · 2024Alternative estimate of religion among foreign residents, demonstrating the uncertainty of modeled data.
2023 International Religious Freedom Report: ItalyU.S. Department of State · 2024Legal framework, recognized accords, minority estimates, and current religious-freedom context.
Rome and migration
Rome Statistical Yearbook 2025Roma Capitale
Municipal-registry population by municipality, citizenship, age, and sex at 31 December 2024.
Single Planning Document 2026–2028Roma CapitaleOfficial summary of 392,090 foreign citizens, 14 percent city share, and leading citizenship communities.
Lazio Population Census 2024Istat · 2026Census-adjusted regional resident population and foreign-citizen composition.
Italy Annual Report 2025Istat · 2025National aging, migration, citizenship, and demographic structure.
History and religious freedom
The Waldensians: HistoryWaldensian Church
Institutional account of Waldensian history and the 1848 Letters Patent.
Twenty Years of Persecution of Pentecostalism in ItalyUniversity of Milan repositoryAcademic study of the 1935–1955 Buffarini-Guidi prohibition and its aftermath.
Article 8 of the Italian ConstitutionItalian SenatePrimary legal text stating that all religious confessions are equally free before the law.
Christian Minorities in United ItalyTreccaniHistorical reference on Protestant minorities, freedom, and restriction after Italian unification.
Rome as an international hub
UN Agencies Headquartered in ItalyItalian Foreign Ministry
Primary government list of FAO, WFP, and IFAD headquarters in Rome.
Air Traffic Data 2025ENACOfficial passenger traffic; Rome Fiumicino was Italy’s busiest airport with 50.9 million passengers.
State of the Great Commission in EuropeLausanne MovementEvangelical missiological analysis of aging, secularization, migration, and partnership with Majority World churches.
Living research
The stable argument and the changing week.
The pages in this research library explain the long-term case for Rome. The Europe & Italy Religion Brief tracks current developments, links each story to its source, and distinguishes demographic data from ministry testimony.
Read the Weekly Brief