Question: In the 19th century opera composer Leo Slezak and the infamous Mozart originated from which European country?

Context articles: Foreign relations of Poland
Leo Slezak
Elks Building and Theater
Woodland Opera House
List of opera festivals
William Vincent Wallace
Music of Belarus
Music of Austria
List of Argentine operas
Kathleen Kuzmick Hansell

The Republic of Poland is a Central European country and member of the European Union and NATO, among others.
 In recent years, despite its occasional but obstinate relations with Russia during the 20th century, Poland has extended its responsibilities and position in European and Western affairs, supporting and establishing friendly foreign relations with both the West and with numerous European countries.
Leo Slezak (] ; 18 August 1873 – 1 June 1946) was a world-famous Moravian tenor.
 He was associated in particular with Austrian opera as well as the title role in Verdi's "Otello".
 He is the father of actors Walter Slezak and Margarete Slezak and grandfather of the actress Erika Slezak.
The Prescott Elks Theater and Performing Arts Center is a classically designed turn of the 20th century opera house seating over 500.
 Completed in 1905 and listed on the National Register of Historical Places as Elks Building and Theater, it was one of many "Elks' Opera Houses" across the country.
 Now over a hundred years later only one still exists.
The Woodland Opera House, listed on the National Register of Historic Places and a California Historical Landmark, is one of four fully functioning 19th century opera houses in California.
 It is a contributing property to the Downtown Historic District of Woodland, California.
This is an inclusive list of opera festivals and summer opera seasons, and music festivals which have opera productions.
 This list may have some overlap with list of early music festivals.
 Opera is part of the Western classical music tradition, and has long been performed for audiences on a large-scale format.
 It started in Italy at the end of the 16th century and soon spread through the rest of Europe.
 In the 18th century, Italian opera continued to dominate most of Europe (except France), attracting foreign composers such as Handel.
 Opera seria was the most prestigious form of Italian opera, until Gluck reacted against its artificiality with his "reform" operas in the 1760s.
 Today the most renowned figure of late 18th century opera is Mozart, and his music is at times the featured attraction of opera and early music festivals.
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(William) Vincent Wallace (11 March 1812 – 12 October 1865) was an Irish composer and musician.
 In his day, he was famous on three continents as a double virtuoso on violin and piano.
 Nowadays, he is mainly remembered as an opera composer of note, with key works such as "Maritana" (1845) and "Lurline" (1847/60), but he also wrote a large amount of piano music (including some virtuoso pieces) that was much in vogue in the 19th century.
 His more modest output of songs and ballads, equally wide-ranging in style and difficulty, was also popular in his day, some numbers being associated with famous singers of the time.
Belarus is an Eastern European country with a rich tradition of folk and religious music.
 The country's folk music traditions can be traced back to the times of the Grand Duchy of Lithuania.
 In the 20th century, the Soviet control of the country somewhat limited musical development because nationally oriented music was considered subversive and dangerous to the Soviet authority.
 The country's musical traditions spread with its people to countries like Russia, Canada, United States, Kazakhstan, Latvia and Ukraine .
 The people of Belarus were exposed mostly to Russian pop music during this period and also after independence in 1991.
 In 2002, however, Alexander Lukashenko has signed a decree requiring 50% of all FM broadcast music to be Belarusian in origin, and since January 1, 2005 the rule was made even stricter (75% of music broadcast each day must be Belarusian).
 However, it does not regulate the language of the songs, so most of the music which is broadcast is still in Russian.
Vienna has been an important center of musical innovation.
 18- and 19th-century composers were drawn to the city due to the patronage of the Habsburgs, and made Vienna the European capital of classical music.
 Joseph Haydn, Wolfgang Amadeus Mozart, Ludwig van Beethoven, Franz Schubert and Johann Strauss II, among others, were associated with the city, with Schubert being born in Vienna.
 During the Baroque period, Slavic and Hungarian folk forms influenced Austrian music.
 Vienna's status began its rise as a cultural center in the early 16th century, and was focused around instruments including the lute.
This is a list of operas by Argentine composers.
 Argentina's first native born opera composer was Francisco Hargreaves (1849-1900) who composed "La gatta bianca" (1875) and "Los estudiantes de Bologna" (1897), followed by Zenón Rolón (1856-1902) who composed several operas as well as operettas and zarzuelas.
 The works of many of the composers from this generation were first performed outside Argentina.
 Native Argentine opera was to develop much more with the massive European (mainly Italian) immigration in the late 19th century and even more with the opening of the Teatro Colón in 1908 where most of the 20th century operas listed here had their world premieres.
 Some of the first operas to treat Argentine subjects or national themes were Arturo Berutti's "Pampa" (1897) based on the life of Juan Moreira and "Yupanki" (1899) based on the life of Inca warrior Manqu Inka Yupanki.
 Also notable in this genre were Felipe Boero's "Tucumán" (1918) set during the Battle of Tucumán and "El matrero" (1929).
 Considered by many to be the quintessential Argentine opera, "El matrero" had a libretto based on gaucho folk tradition and incorporated Argentine folk melodies and a traditional gaucho dance.
 The Spanish playwright Federico García Lorca was also the inspiration for several Argentine operas.
 His plays, "La zapatera prodigiosa" and "Bodas de sangre", were the basis of operas by Juan José Castro, while Osvaldo Golijov's 2003 opera "Ainadamar" is based on events in the playwright's life.
Kathleen Kuzmick Hansell, "née" Kuzmick, (born 21 September 1941) is an American musicologist and organist.
 Amongst her publications are pioneering research on the role of dance in 18th century opera and critical editions of opera scores by Mozart, Rossini, and Verdi.