Iași (UKˈjæʃi , USˈjɑːʃ(i) , ˈjaʃj; also known by other alternative names), also referred to mostly historically as Jassy (UKˈjæsi , USˈjɑːsi ), is the third largest city in Romania and the seat of Iași County. Located in the historical region of Moldavia, it has traditionally been one of the leading centres of Romanian social, cultural, academic and artistic life. The city was the capital of the Principality of Moldavia from 1564 to 1859, then of the United Principalities from 1859 to 1862, and the capital of Romania from 1916 to 1918.
Known as the Cultural Capital of Romania, Iași is a symbol of Romanian history. Historian Nicolae Iorga stated that "there should be no Romanian who does not know of it". Still referred to as "The Moldavian Capital", Iași is the main economic and business centre of Romania's Moldavian region. In December 2018, Iași was officially declared the Historical Capital of Romania.
At the 2021 census, the city-proper had a population of 271,692, its metropolitan area had a population of 423,154, whereas more than 500,000 people live within its peri-urban area. Counting 500,668 residents (as of 2018), the Iași urban area is the second most populous in Romania after Bucharest.
Home to the oldest Romanian university and to the first engineering school, Iași is one of the most important education and research centres of the country, accommodating over 60,000 students in five public universities. The social and cultural life revolves around the Vasile Alecsandri National Theatre (the oldest in Romania), the Moldova State Philharmonic, the Opera House, the Iași Athenaeum, the Botanical Garden (the oldest and largest in Romania), the Central University Library (the oldest in Romania), the cultural centres and festivals, an array of museums, memorial houses, religious and historical monuments. The city is also known as the site of the largest Romanian pilgrimage which takes place every year, in October.
Scholars have different theories on the origin of the name "Iași".