The city of Helsinki, Finland (belonging to Sweden at the time) is founded by King Gustav I of Sweden.

Gustav I, born Gustav Eriksson of the Vasa noble family and later known as Gustav Vasa (12 May 1496 29 September 1560), was King of Sweden from 1523 until his death in 1560, previously self-recognised Protector of the Realm (Riksfrestndare) from 1521, during the ongoing Swedish War of Liberation against King Christian II of Denmark, Norway and Sweden. Gustav rose to lead the rebel movement following the Stockholm Bloodbath, where his father was executed. Gustav's election as king on 6 June 1523 and his triumphant entry into Stockholm eleven days later marked Sweden's final secession from the Kalmar Union.As king, Gustav proved an energetic administrator with a ruthless streak not inferior to his predecessor's, brutally suppressing subsequent uprisings (three in Dalarna which had once been the first region to support his claim to the throne one in Vstergtland, and one in Smland). He worked to raise taxes and bring about a Reformation in Sweden, replacing the prerogatives of local landowners, noblemen and clergy with centrally appointed governors and bishops. His 37-year rule, which was the longest of an adult Swedish king to that date (subsequently passed by Gustav V and Carl XVI Gustav) saw a complete break with not only the Danish - Norwegian supremacy but also the Roman Catholic Church, whose assets were nationalised, with the Lutheran Church of Sweden established under his personal control. He became the first truly autocratic native Swedish sovereign and was a skilled bureaucrat and propagandist, with tales of his largely fictitious adventures during the liberation struggle still widespread to this day. In 1544, he abolished Medieval Sweden's elective monarchy and replaced it with a hereditary monarchy under the House of Vasa, which held the Swedish throne until 1654. Three of his sons, Eric XIV, John III and Charles IX, held the kingship at different points.Gustav I has subsequently been labelled the founder of modern Sweden, and the "father of the nation". Gustav liked to compare himself to Moses, whom he believed to have also liberated his people and established a sovereign state. As a person, Gustav was known for ruthless methods and a bad temper, but also a fondness for music and had a certain sly wit and ability to outmaneuver and annihilate his opponents. He founded one of the oldest orchestras of the world, Kungliga Hovkapellet (Royal Court Orchestra); thus Royal housekeeping accounts from 1526 mention twelve musicians including wind players and a timpanist but no string players. Today Kungliga Hovkapellet is the orchestra of the Royal Swedish Opera.

Helsinki ( HEL-sink-ee or (listen) hel-SINK-ee; Finnish: [ˈhelsiŋki] (listen); Swedish: Helsingfors, Finland Swedish: [helsiŋˈforsː] (listen); Latin: Helsingia) is the capital, primate, and most populous city of Finland. Located on the shore of the Gulf of Finland, it is the seat of the region of Uusimaa in southern Finland, and has a population of 658,864. The city's urban area has a population of 1,268,296, making it by far the most populous urban area in Finland as well as the country's most important center for politics, education, finance, culture, and research; while Tampere in the Pirkanmaa region, located 179 kilometres (111 mi) to the north from Helsinki, is the second largest urban area in Finland. Helsinki is located 80 kilometres (50 mi) north of Tallinn, Estonia, 400 km (250 mi) east of Stockholm, Sweden, and 300 km (190 mi) west of Saint Petersburg, Russia. It has close historical ties with these three cities.

Together with the cities of Espoo, Vantaa, and Kauniainen (and surrounding commuter towns, including the eastern neighboring municipality of Sipoo), Helsinki forms the Greater Helsinki metropolitan area, which has a population of over 1.5 million. Often considered to be Finland's only metropolis, it is the world's northernmost metro area with over one million people as well as the northernmost capital of an EU member state. After Copenhagen and Stockholm, Helsinki is the third largest municipality in the Nordic countries. Finnish and Swedish are both official languages. The city is served by the international Helsinki Airport, located in the neighboring city of Vantaa, with frequent service to many destinations in Europe and Asia.

Helsinki was the World Design Capital for 2012, the venue for the 1952 Summer Olympics, and the host of the 52nd Eurovision Song Contest in 2007.

Helsinki has one of the world's highest standards of urban living. In 2011, the British magazine Monocle ranked Helsinki the world's most liveable city in its liveable cities index. In the Economist Intelligence Unit's 2016 liveability survey, Helsinki was ranked ninth among 140 cities. In July 2021, the American magazine Time ranked Helsinki one of the greatest places in the world in 2021 as a city that "can grow into a sprouting cultural nest in the future," and which has already been known in the world as an environmental pioneer. An international Cities of Choice survey conducted in 2021 by the consulting firm Boston Consulting Group and the BCG Henderson Institute raised Helsinki the third best city in the world to live, with London and New York City ranking the first and the second. Also, together with Rovaniemi in the Lapland region, Helsinki is one of Finland's most significant tourist cities in terms of foreign tourism.