The holiday has deep roots in Catholic tradition – it marks Mary’s “ascent to heaven” according to Catholic doctrine. In Eastern Orthodox churches (where it’s often called the Dormition of the Theotokos), August 15 is likewise a central feast day.

The date has been celebrated since the early centuries of Christianity (established by the 6th–7th centuries) and remains a Holy Day of Obligation in the Catholic Church, meaning the faithful attend special Masses on this day. Many towns host religious processions, masses, and community festivals on August 15 to honour the Virgin Mary’s assumption.

Because of its religious importance, August 15 (Assumption Day) is a public holiday in numerous European countries. Nations with strong Catholic or Orthodox heritage have long designated this date as a nationwide day off, despite secular governance in some cases (for example, officially secular France still observes Assumption Day).

Major Catholic-majority countries such as France, Italy, Spain, Poland, Austria, Belgium, and Portugal all mark August 15 as a national public holiday, as do several smaller European states.

Predominantly Orthodox countries like Greece, Cyprus, and Romania also treat this day as a national holiday. Even microstates and regions with Catholic traditions (e.g. Andorra, San Marino, Monaco, Malta, and Liechtenstein) celebrate August 15 with official closures.

In total, well over a dozen European countries suspend work nationwide on this date in honour of the Assumption.

However, in a few countries, the observance is regional rather than nationwide. For instance, Germany does not have a federal public holiday on August 15, but the day is a day off in its heavily Catholic states of Bavaria (mostly in communities with Catholic majorities) and the state of Saarland.

Switzerland similarly observes August 15 only in its Catholic-majority cantons (about 12 of the 26 cantons, such as Lucerne, Ticino, Valais, and others). Parts of Bosnia and Herzegovina with significant Catholic populations also recognise August 15 as a local holiday.

On the other hand, countries with largely Protestant or secular backgrounds – for example, the UK, the Netherlands, and most of Scandinavia – do not treat August 15 as a day off, reflecting the holiday’s specifically Catholic/Orthodox origins.