Question: Are Measure for Measure and Mathis der Maler both fictional?

Context articles: Mathis der Maler (opera)
Symphony: Mathis der Maler
Atomic radius
Measure for Measure
Inga Nielsen
Van der Pauw method
Paul Hindemith
Ida Kerkovious
Johannes Rebmann
The Weapons of Youth

Mathis der Maler ("Matthias the Painter") is an opera by Paul Hindemith.
 The opera's genesis lay in Hindemith's interest in the Reformation.
 The work's protagonist, Matthias Grünewald, was an actual historical figure who flourished in that era, and whose art, in particular the Isenheim Altarpiece, inspired many creative figures in the early 20th century, including Joris-Karl Huysmans's novel "Là-bas".
Symphony: Mathis der Maler ("Matthias the Painter") is among the most famous orchestral works of German composer Paul Hindemith.
 Music from the symphony was incorporated into, or reworked for, Hindemith's opera "Mathis der Maler", which concerns the painter Matthias Grünewald (or Neithardt).
The atomic radius of a chemical element is a measure of the size of its atoms, usually the mean or typical distance from the center of the nucleus to the boundary of the surrounding cloud of electrons.
 Since the boundary is not a well-defined physical entity, there are various non-equivalent definitions of atomic radius.
 Three widely used definitions of atomic radius are: Van der Waals radius, ionic radius, and covalent radius.
Measure for Measure is a play by William Shakespeare, believed to have been written in 1603 or 1604.
 Originally published in the "First Folio" of 1623, where it was listed as a comedy, the play's first recorded performance occurred in 1604.
 The play's main themes include justice, "mortality and mercy in Vienna," and the dichotomy between corruption and purity: "some rise by sin, and some by virtue fall."
 Mercy and virtue prevail, as the play does not end tragically, with virtues such as compassion and forgiveness being exercised at the end of the production.
 While the play focuses on justice overall, the final scene illustrates that Shakespeare intended for moral justice to temper strict civil justice: a number of the characters receive understanding and leniency, instead of the harsh punishment to which they, according to the law, could have been sentenced.
Inga Nielsen (2 June 1946 – 10 February 2008) was a Danish soprano who had an active international opera career from 1971 to 2006.
 A child prodigy, Nielsen performed on American radio during the 1950s, beginning at the age of six, and also released some commercial recordings of Danish folk songs and Christmas carols as a child.
 She began her opera career performing parts in the lyric soprano repertory and then became an admired singer of dramatic soprano roles, beginning in the late 1980s.
 She was a particularly renowned interpreter of the roles of Konstanze in Wolfgang Amadeus Mozart's "Die Entführung aus dem Serail" and the title role in Richard Strauss's "Salome".
 She excelled in portraying some of the more rarely heard and demanding dramatic soprano roles such as the woman in Arnold Schoenberg's "Erwartung", Ursula in "Mathis der Maler" and Jenny in "Rise and Fall of the City of Mahagonny".
The van der Pauw Method is a technique commonly used to measure the resistivity and the Hall coefficient of a sample.
 Its power lies in its ability to accurately measure the properties of a sample of any arbitrary shape, so long as the sample is approximately two-dimensional (i.e. it is much thinner than it is wide), solid (no holes), and the electrodes are placed on its perimeter.
 The van der Pauw Method employs a four-point probe placed around the perimeter of the sample, in contrast to the linear four point probe: this allows the van der Pauw method to provide an average resistivity of the sample, whereas a linear array provides the resistivity in the sensing direction.
 This difference becomes important for anisotropic materials, which can be properly measured using the Montgomery Method, an extension of the van der Pauw Method.
Paul Hindemith ( ) (16 November 1895 – 28 December 1963) was a prolific German composer, violist, violinist, teacher and conductor.
 Notable compositions include his song cycle "Das Marienleben" (1923), "Der Schwanendreher" for viola and orchestra (1935), and opera "Mathis der Maler" (1938).
 Hindemith's most popular work, both on record and in the concert hall, is likely the "Symphonic Metamorphosis of Themes by Carl Maria von Weber", written in 1943.
Ida Kerkovious (1879–1970) was one of twelve children born to an upper class German family.
 She was taught piano at an all-girls secondary school before she attending a private institution in Riga.
 In Riga she studied with Adolf Holzel and grew to have an acute understanding of paint and color.
 She became an assistant and theorist at the Königlich Württembergische Akademie der Bildenden Künste in Stuttgart before losing her citizenship, and thus her place at the academy, during World War I.
 Kerkovious then taught foreign students in similar positions and registered at the Bauhaus, where she eventually joined the weaving workshop.
 Her income between the wars came primarily from the weaving workshop and through the secret sale of Kerkovius’s art by art dealer Bekker vom Rath.
 Her studio in Stuttgart was bombed during World War II, destroying many of her existing paintings.
 She was later named a member of the artists’ guild of Esslingen/Neckar and was awarded first prize for work in the 1955 exhibition Ischia im Bilde deutscher Maler.
Johannes Rebmann (January 16, 1820 – October 4, 1876) was a German missionary and explorer credited with feats including being the first European, along with his colleague Johann Ludwig Krapf, to enter Africa from the Indian Ocean coast.
 In addition, he was the first European to find Kilimanjaro.
 News of Rebmann's discovery was published in the Church Missionary Intelligencer in May 1849, but disregarded as mere fantasy for the next twelve years.
 The Geographical Society of London held that snow could not possibly occur let alone persist in such latitudes and considered the report to be the hallucination of a malaria-stricken missionary.
 It was only in 1861 that researchers began their efforts to measure Kilimanjaro.
 Expeditions to Tanzania between 1861 and 1865, led by the German Baron Karl Klaus von der Decken, confirmed Rebmann’s report.
 Together with his colleague Johann Ludwig Krapf he also discovered Mt. Kenya.
 Their work there is also thought to have had effects on future African expeditions by Europeans, including the exploits of Sir Richard Burton, John Hanning Speke, and David Livingstone.
 After losing most of his eyesight and entering into a brief marriage, he died of pneumonia.
The Weapons of Youth (German: Die Waffen der Jugend) is a 1913 German silent film directed by Friedrich Müller and starring Gertrud Gräbner, Curt Maler and Hans Staufen.