On This Day

San Marino, one of the smallest nations in the world and the world's oldest republic still in existence, is founded by S

San Marino, one of the smallest nations in the world and the world's oldest republic still in existence, is founded by Saint Marinus

San Marino, officially the Republic of San Marino (RSM), is a landlocked country in Southern Europe, completely surrounded by Italy. Located on the northeastern slopes of the Apennine Mountains, it is the larger of two microstates within Italy, the other being Vatican City. San Marino is the fifth-smallest country in the world, with a land area of just over 61 km2 (23.5 mi2) and a population of 34,042 as of 2025. Its capital, the City of San Marino, sits atop Monte Titano, while its largest settlement is Dogana, in the municipality of Serravalle.

San Marino claims to have been founded in AD 301 and to be the oldest extant sovereign state and the oldest constitutional republic.

Historical Significance

San Marino, officially the Republic of San Marino (RSM), is a landlocked country in Southern Europe, completely surrounded by Italy.

Events Before

  1. Roman emperor Maximianus introduces tetrarchy (rule of four people) elevating Galerius and Constantius Chlorus to Caesar

    Roman emperor Maximianus introduces tetrarchy (rule of four people) elevating Galerius and Constantius Chlorus to Caesar

  2. BC The oldest known Roman temple to Venus is founded, initiating the institution of Vinalia Rustica (grape harvest festi

    BC The oldest known Roman temple to Venus is founded, initiating the institution of Vinalia Rustica (grape harvest festival)

  3. Eighth recorded perihelion passage of Halley's Comet

    Halley's Comet is the only known short-period comet that is consistently visible to the naked eye from Earth, appearing every 72–80 years, though with the majority of recorded apparitions (25 of 30)...

  4. St Gaius ends his reign as Catholic Pope

    St Gaius ends his reign as Catholic Pope

  5. St Marcellinus begins his reign as Catholic Pope

    The pope is the bishop of Rome and the head of the worldwide Catholic Church. He is also known as the supreme pontiff, Roman pontiff, or sovereign pontiff.

Events After

  1. First official Roman edict for persecution of Christians issued by Emperor Diocletian at Nicomedia, ordering all churche

    First official Roman edict for persecution of Christians issued by Emperor Diocletian at Nicomedia, ordering all churches to be closed and scriptures burnt

  2. On a voyage preaching the gospel, Saint Fermin of Pamplona is beheaded in Amiens, France

    On a voyage preaching the gospel, Saint Fermin of Pamplona is beheaded in Amiens, France

  3. Constantine I is proclaimed Roman Emperor by his troops

    Constantine I (27 February 272 – 22 May 337), also known as Constantine the Great, or known mononymously as Constantine, was Roman emperor from AD 306 to 337 and the first Roman emperor to convert to...

  4. Martyrdom of Saint Adrian of Nicomedia, a Roman guard, who is beheaded for converting to Christianity under Roman Empero

    Martyrdom of Saint Adrian of Nicomedia, a Roman guard, who is beheaded for converting to Christianity under Roman Emperor Galerius

  5. Roman Emperor Constantine I marries Fausta, daughter of the Emperor Maximian, later murdering her in 326

    Roman Emperor Constantine I marries Fausta, daughter of the Emperor Maximian, later murdering her in 326

More from the 300s

Frequently Asked Questions

What happened on September 3, 301?
San Marino, officially the Republic of San Marino (RSM), is a landlocked country in Southern Europe, completely surrounded by Italy. Located on the northeastern slopes of the Apennine Mountains, it is the larger of two microstates within Italy, the other being Vatican City. San Marino is the fifth-smallest country in the world, with a land area of just over 61 km2 (23.5 mi2) and a population of 34,042 as of 2025.
Why is San Marino, one of the smallest nations in the world and the world's oldest r... significant?
San Marino, officially the Republic of San Marino (RSM), is a landlocked country in Southern Europe, completely surrounded by Italy.

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