Question: When did the country that contains Lavia join the Russian Empire?

full_context: Document 1: Russian language: According to figures published in 2006 in the journal "Demoskop Weekly" research deputy director of Research Center for Sociological Research of the Ministry of Education and Science (Russia) Arefyev A. L., the Russian language is gradually losing its position in the world in general, and in Russia in particular. In 2012, A. L. Arefyev published a new study "Russian language at the turn of the 20th-21st centuries", in which he confirmed his conclusion about the trend of further weakening of the Russian language in all regions of the world (findings published in 2013 in the journal "Demoskop Weekly"). In the countries of the former Soviet Union the Russian language is gradually being replaced by local languages. Currently the number speakers of Russian language in the world depends on the number of Russians in the world (as the main sources distribution Russian language) and total population Russia (where Russian is an official language).
Document 2: Russian language: The language was first introduced in North America when Russian explorers voyaged into Alaska and claimed it for Russia during the 1700s. Although most colonists left after the United States bought the land in 1867, a handful stayed and preserved the Russian language in this region to this day, although only a few elderly speakers of this unique dialect are left. Sizable Russian-speaking communities also exist in North America, especially in large urban centers of the U.S. and Canada, such as New York City, Philadelphia, Boston, Los Angeles, Nashville, San Francisco, Seattle, Spokane, Toronto, Baltimore, Miami, Chicago, Denver and Cleveland. In a number of locations they issue their own newspapers, and live in ethnic enclaves (especially the generation of immigrants who started arriving in the early 1960s). Only about 25% of them are ethnic Russians, however. Before the dissolution of the Soviet Union, the overwhelming majority of Russophones in Brighton Beach, Brooklyn in New York City were Russian-speaking Jews. Afterward, the influx from the countries of the former Soviet Union changed the statistics somewhat, with ethnic Russians and Ukrainians immigrating along with some more Russian Jews and Central Asians. According to the United States Census, in 2007 Russian was the primary language spoken in the homes of over 850,000 individuals living in the United States.
Document 3: Iivantiira: Iivantiira is a medium-sized lake of Finland. It belongs to Oulujoki main catchment area and it is situated in Kuhmo municipality in the Kainuu region. Iivantiira is connected to the lake Juttuajärvi with Hoikka strait, and together they form a lake Iivantiira–Juttuajärvi. The lake belongs to Änättijärvi–Lentiira–Iivantiira–Lentua-Sotkamo kayaking route named Tervareitti, "The Tar Route".
Document 4: Maalaiskunta: Maalaiskunta (Finnish), landskommun (Swedish), "rural municipality", abbreviated "mlk" was one of the four types of municipality in Finland in 1865–1976. Other types in 1865–1959 were city (in Finnish "kaupunki") and market town (in Finnish "kauppala"), in 1960–1976 old city (in Finnish "vanha kaupunki"), new city (in Finnish "uusi kaupunki") and market town. Maalaiskunta was the most common type of municipality. In the 1977 reform, all municipalities were given fully equal legal standing. Previous "maalaiskunta"s associated with a city retained their name. For example, Rovaniemen maalaiskunta ("the rural municipality of Rovaniemi) surrounded the city of Rovaniemi, but were independently governed. From 2009, no municipalities will carry this name any more, after the merger of Jyväskylä and Jyväskylän mlk.
Document 5: Levi, Finland: Levi is a fell located in Finnish Lapland, and the largest ski resort in Finland. The resort is located in Kittilä municipality and is served by Kittilä Airport and Kolari railway station. At a latitude of 67.8° north, it is located approximately north of the Arctic Circle.
Document 6: Lavia, Finland: Lavia is a former municipality in the region of Satakunta, in Finland. It was merged with the city of Pori on 1 January 2015.
Document 7: Lappeenranta: Lappeenranta () is a city and municipality situated on the shore of the lake Saimaa in southeastern Finland, about from the Russian border. It belongs to the region of South Karelia. With approximately inhabitants () Lappeenranta is the largest city in Finland. The neighboring municipality of Joutseno was consolidated with Lappeenranta on January 1, 2009, and the neighboring municipality of Ylämaa on January 1, 2010. Lappeenranta is known as an international university city in Finland with Lappeenranta University of Technology and Saimaa University of Applied Sciences which together have approximately 13,000 students from 68 countries. Lappeenranta is also a commercial centre of South-East Finland and the meeting point of the EU and Russia, 215 km from both Helsinki and St. Petersburg. Location on the southern shore of Lake Saimaa makes the city the region's centre for tourism. Lappeenranta is the second most visited city by Russian tourists in Finland after Helsinki and it competes with Helsinki for the largest share of tax-free sales in Finland. Lappeenranta is a model for renewable energies and a clean living environment. Lappeenranta was the only Finnish city among the 14 finalists in the international Earth Hour City Challenge 2014, organized by WWF.
Document 8: Kalanti: Kalanti (, officially "Uusikirkko Tl" during 1915–1936) is a former municipality in Southwest Finland region, Finland. Kalanti is first mentioned in historical sources 1332. It was merged with Uusikaupunki in 1993.
Document 9: Russian language: Ethnic Russians constitute 25.5% of the country's current population and 58.6% of the native Estonian population is also able to speak Russian. In all, 67.8% of Estonia's population can speak Russian. Command of Russian language, however, is rapidly decreasing among younger Estonians (primarily being replaced by the command of English). For example, if 53% of ethnic Estonians between 15 and 19 claim to speak some Russian, then among the 10- to 14-year-old group, command of Russian has fallen to 19% (which is about one-third the percentage of those who claim to have command of English in the same age group).
Document 10: Russian language: As the Grand Duchy of Finland was part of the Russian Empire from 1809 to 1918, a number of Russian speakers have remained in Finland. There are 33,400 Russian-speaking Finns, amounting to 0.6% of the population. Five thousand (0.1%) of them are late 19th century and 20th century immigrants or their descendants, and the remaining majority are recent immigrants who moved there in the 1990s and later.[citation needed] Russian is spoken by 1.4% of the population of Finland according to a 2014 estimate from the World Factbook.
Document 11: Russian language: In Kazakhstan Russian is not a state language, but according to article 7 of the Constitution of Kazakhstan its usage enjoys equal status to that of the Kazakh language in state and local administration. According to estimates from Demoskop Weekly, in 2004 there were 4,200,000 native speakers of Russian in the country, and 10 million active speakers. 63% of the population was fluent in Russian in 2006, and 46% used it as the main language with family, friends or at work. According to a 2001 estimate from the World Factbook, 95% of the population can speak Russian. Large Russian-speaking communities still exist in northern Kazakhstan, and ethnic Russians comprise 25.6% of Kazakhstan's population. The 2009 census reported that 10,309,500 people, or 84.8% of the population aged 15 and above, could read and write well in Russian, as well as understand the spoken language.
Document 12: Leivonmäki: Leivonmäki is a former municipality of Finland. It became a part of Joutsa in 2008. It is known for its marshy grounds and its national park. First inhabitants are mentioned in 1564. It has been a municipality since 1870.
Document 13: Saari, Finland: It was located in the province of Southern Finland and is part of the South Karelia region. The municipality had a population of 1,411 (2003) and covered an area of 183.08 km² of which 15.70 km² is water. The population density was 8.4 inhabitants per km².
Document 14: Russian language: Significant Russian-speaking groups also exist in Western Europe. These have been fed by several waves of immigrants since the beginning of the 20th century, each with its own flavor of language. The United Kingdom, Spain, Portugal, France, Italy, Belgium, Greece, Brazil, Norway, and Austria have significant Russian-speaking communities. According to the 2011 Census of Ireland, there were 21,639 people in the nation who use Russian as a home language. However, of this only 13% were Russian nationals. 20% held Irish citizenship, while 27% and 14% were holding the passports of Latvia and Lithuania respectively.
Document 15: Russian language: In Georgia Russian has no official status, but it's recognised as a minority language under the Framework Convention for the Protection of National Minorities. According to estimates from Demoskop Weekly, in 2004 there were 130,000 native speakers of Russian in the country, and 1.7 million active speakers. 27% of the population was fluent in Russian in 2006, and 1% used it as the main language with family, friends or at work. Russian is the language of 9% of the population according to the World Factook. Ethnologue cites Russian as the country's de facto working language.
ground_truth: 1809
sub_queries: Lavia >> country Answer: Finland
When did Finland join the Russian Empire? Answer: 1809