Saint Piran or Perran (traditionally in Cornwall, saints are simply named, without this title) (Cornish: Peran) is an early 6th century Cornish abbot and saint, supposedly of Irish origin.

He is the patron saint of tin-miners, and is also generally regarded as the patron saint of Cornwall, although Saint Michael and Saint Petroc also have some claim to this title.Saint Piran's Flag, a white cross on a black background, is used as a symbol of Cornwall. Saint Piran's Day takes place on 5 March.

Piran is the most famous of all the saints said to have come to Cornwall from Ireland. By at least the 13th century, he had become identified with the Irish Saint Ciarán of Saighir who founded the monastery at Seir-Kieran (Saighir) in County Offaly. This was due to the widely recognised ability of the P-Celtic or Brythonic letter 'P' to transform into the Q-Celtic or Gaelic letter 'C'. The 14th century 'Life of Saint Piran', probably written at Exeter Cathedral, is a complete copy of an earlier Irish life of Saint Ciarán of Saighir, with different parentage and a different ending that takes into account Piran's works in Cornwall, and especially details of his death and the movements of his Cornish shrine; thus "excising the passages which speak of his burial at Saighir" (Doble). However, there is no shrine to him in Ireland. 5 March is the traditional feast day of both Saint Ciarán of Saighir and Saint Piran, but the Calendar of Launceston Church records an alternative date of 18 November for the latter.

Piran (Italian: Pirano) is a town in the eponymous municipality in southwestern Slovenia on the Gulf of Piran on the Adriatic Sea. It is one of the three major towns of Slovenian Istria. The town resembles a large open-air museum, with medieval architecture and a rich cultural heritage. Narrow streets and compact houses give the town its special charm. Piran is the administrative centre of the local area and one of Slovenia's major tourist attractions.

In the pre-Roman era, the hills in the Piran area were inhabited by Illyrian Histri tribes who were farmers, hunters and fishermen. They were also pirates who disrupted Roman trade in the north Adriatic Sea. The Piran peninsula was incorporated into the Roman Empire in 178 and 177 BC and settled in the following years with rural homes (ville rusticae).

The decline of the Empire, from the 5th century AD onwards, and incursions by the Avars and Slavs at the end of the 6th century, prompted the Roman population to withdraw into easily defensible locations such as islands or peninsulas. This started local urbanisation and by the 7th century, under Byzantine rule, Piran had become heavily fortified. Despite the defences, the Franks conquered Istria in 788 and Slavs settled in the region. By 952, Piran had become a part of the Holy Roman Empire. The earliest reliable records of the area are in the 7th century work Cosmographia by an anonymous cleric of Ravenna. The name of the town most probably originates from the Greek "pyrranos", which means "red", because of the reddish flysch stones commonly found in the town's area.