Question: What was the pen name of the husband of Grand Duchess Yelizaveta Mavrikiyevna ?

full_context: Document 1: Prince Georgy Konstantinovich of Russia: Prince Georgy Konstantinovich of Russia (6 May 1903 – 7 November 1938), was the youngest son of Grand Duke Konstantin Konstantinovich of Russia and his wife Grand Duchess Yelizaveta Mavrikiyevna.
Document 2: Princess Nina Georgievna of Russia: Princess Nina Georgievna of Russia, (Russian: Нина Георгиевна ) (20 June 1901 – 27 February 1974), was the elder daughter of Grand Duke George Mikhailovich and Grand Duchess Maria Georgievna of Russia. A great-granddaughter of Tsar Nicholas I of Russia, she left her native country in 1914, before World War I finished her education in England and spent the rest of her life in exile. In London in 1922, she married Prince Paul Chavchavadze, a descendant of the last king of Georgia. They had one child, Prince David Chavchavadze, born there two years later. In 1927 the family of three moved to the United States and settled in New York. In 1939 they bought a home in Wellfleet, Massachusetts. Princess Nina was an artist, her husband worked as an author; he wrote five books and translated several others. Their son, Prince David Chavchavadze, served with the U.S. Army during World War II and, thanks in part to his knowledge of Russian, eventually became a CIA officer. After his retirement, he wrote his memoirs and published those of his grandmother, Grand Duchess George, as well as a book about the grand dukes of Russia.
Document 3: Konstantine Gamsakhurdia: Konstantine Gamsakhurdia (Georgian: კონსტანტინე გამსახურდია ) (May 3, 1893 – July 17, 1975) was a Georgian writer and public figure, who, along with Mikheil Javakhishvili, is considered to be one of the most influential Georgian novelists of the 20th century. Educated and first published in Germany, he married Western European influences to purely Georgian thematic to produce his best works, such as "The Right Hand of the Grand Master" and "David the Builder". Hostile to the Soviet rule, he was, nevertheless, one of the few leading Georgian writers to have survived the Stalin-era repressions, including his exile to a White Sea island and several arrests. His works are noted for their character portrayals of great psychological insight. Another major feature of Gamsakhurdia's writings is a new subtlety he infused into Georgian diction, imitating an archaic language to create a sense of classicism.
Document 4: Grand Duke Konstantin Konstantinovich of Russia: Grand Duke Konstantin Konstantinovich of Russia (Russian: Константи́н Константи́нович ; ] ; 22 August 1858 in Strelna – 15 June 1915 in Pavlovsk) was a grandson of Emperor Nicholas I of Russia, and a poet and playwright of some renown. He wrote under the pen name "K.R.", initials of his given name and family name, Konstantin Romanov.
Document 5: Nicholas I of Russia: Nicholas I (Russian: Николай I Павлович , "Nikolay I Pavlovich" ; 6 July [O.S. 25 June] 1796 – 2 March [O.S. 18 February] 1855 ) was the Emperor of Russia from 1825 until 1855. He was also the King of Poland and Grand Duke of Finland. He is best known as a political conservative whose reign was marked by geographical expansion, repression of dissent, economic stagnation, poor administrative policies, a corrupt bureaucracy, and frequent wars that culminated in Russia's defeat in the Crimean War of 1853–56. His biographer Nicholas V. Riasanovsky says that Nicholas displayed determination, singleness of purpose, and an iron will, along with a powerful sense of duty and a dedication to very hard work. He saw himself as a soldier—a junior officer totally consumed by spit and polish. A handsome man, he was highly nervous and aggressive. Trained as an engineer, he was a stickler for minute detail. In his public persona, says Riasanovsky, "Nicholas I came to represent autocracy personified: infinitely majestic, determined and powerful, hard as stone, and relentless as fate." His reign had an ideology called "Official Nationality" that was proclaimed officially in 1833. It was a reactionary policy based on orthodoxy in religion, autocracy in government, and Russian nationalism. He was the younger brother of his predecessor, Alexander I. Nicholas inherited his brother's throne despite the failed Decembrist revolt against him and went on to become the most reactionary of all Russian leaders. His aggressive foreign policy involved many expensive wars, having a disastrous effect on the empire's finances.
Document 6: Nestor Kukolnik: Nestor Vasilievich Kukolnik (Russian: Нестор Васильевич Кукольник ) (1809–1868) was a Russian playwright and prose writer of Carpatho-Rusyn origin. Immensely popular during the early part of his career, his works were subsequently dismissed as sententious and sentimental. Today, he is best remembered for having contributed to the libretto of the first Russian opera, "A Life for the Tsar" by Mikhail Glinka. Glinka also set many of his lyrics to music.
Document 7: Prince George, Duke of Kent: Prince George, Duke of Kent, {'1': ", '2': ", '3': ", '4': "} (George Edward Alexander Edmund; 20 December 1902 – 25 August 1942) was the fourth son of George V of the United Kingdom and Queen Mary.
Document 8: Konstantin Aksakov: Konstantin Sergeyevich Aksakov (Russian: Константи́н Серге́евич Акса́ков ) (10 April 1817, Novo-Aksakov, Orenburg Governorate – 19 December 1860, Zakynthos, US of the Ionian Islands) was a Russian critic and writer, one of the earliest and most notable Slavophiles. He wrote plays, social criticism, and histories of the ancient Russian social order. His father Sergey Aksakov and his sister Vera Askakova were writers, and his younger brother, Ivan Aksakov, was a journalist.
Document 9: Konstantin Somov: Konstantin Andreyevich Somov (Russian: Константин Андреевич Сомов, November 30, 1869 – May 6, 1939) was a Russian artist associated with the "Mir iskusstva". Born into a family of a major art historian and Hermitage Museum curator Andrey Ivanovich Somov, he became interested in 18th-century art and music at an early age.
Document 10: Grand Duchess Alexandra Georgievna of Russia: Grand Duchess Alexandra Georgievna of Russia (Russian: Алекса́ндра Гео́ргиевна ); "née" Princess Alexandra of Greece and Denmark (Greek: Πριγκίπισσα Αλεξάνδρα της Ελλάδας και της Δανίας ); 30 August 1870 – 24 September 1891) was the third child and firstborn daughter of King George I and Queen Olga of Greece, who herself was a daughter of a Russian grand duke, and was also a grandchild of Denmark's King Christian IX and Queen Louise. She was a sister to Constantine I of Greece, and thus aunt of three kings and two queens, Constantine's three sons, who all became kings of Greece, and two of his daughters, who were queens, in name, of Romania and Croatia, respectively. She was also first cousin of Tsar Nicholas II of Russia, King George V of the United Kingdom, and both King Haakon VII and Queen Maud of Norway, as well as a paternal aunt of Prince Philip, Duke of Edinburgh.
Document 11: Prince Nicholas of Greece and Denmark: Prince Nicholas of Greece and Denmark (, 22 January 1872 – 8 February 1938), of the Glücksburg branch of the House of Oldenburg, was the fourth child and third son of King George I of Greece, and of Queen Olga. He was known as "Greek Nicky" in the family to distinguish him from his paternal first cousin Emperor Nicholas II of Russia. Prince Nicholas was a talented painter, often signing his works as "Nicolas Leprince."
Document 12: Karl-Konstantin von Habsburg: Karl-Konstantin von Habsburg (Given names: Karl-Konstantin Michael Stephan Maria; born on 20 July 2004 in Budapest) referred to in Austria as Karl-Konstantin Habsburg-Lothringen, in Hungary as Habsburg Károly Konstantin, and also as Archduke Karl-Konstantin of Austria, is the only son of Georg von Habsburg and Duchess Eilika of Oldenburg. s of 2016 , he is considered third in line of succession to the former Austro-Hungarian throne. He is the great-grandson of Emperor Charles I of Austria through his grandfather Otto von Habsburg. Through his maternal grandfather, he is a descendant of George II of Great Britain, and would therefore be in line for the British throne were he not a Catholic and barred by the Act of Settlement.
Document 13: Grigory Kugushev: Prince Grigory Vasilyevich Kugushev (Russian: Григорий Васильевич Кугушев , 17 March 1824, – 3 October 1871) was a Russian writer, poet and playwright whose comedies (including "Goluboi Kapot", Blue Hood; "Pari", The Bet; "Priyomysh", Foster) had great (if not very lasting) success in the Russian Imperial Theatres in 1850s. More substantial and critically acclaimed were Kugushev's works of fiction, notably "Kornet Otletayev" (Корнет Отлетаев, a three-part novella, first published by "Russky Vestnik" in 1856) and the four-part novel "Postoronneye Vliyaniye" (Постороннее влияние, 1858—1859). He also wrote the libretto for the epic drama opera "Mazeppa" (1859) by Baron
Document 14: Mikalojus Konstantinas Čiurlionis: Mikalojus Konstantinas Čiurlionis (Polish: "Mikołaj Konstanty Czurlanis" ; 22 September [O.S. 10 September] 1875 – 10 April [O.S. 28 March] 1911 ) was a Lithuanian painter, composer and writer.
Document 15: Princess Vera Constantinovna of Russia: Princess Vera Constantinovna of Russia, also Vera Konstantinovna (Russian: Вера Константиновна Романова ; 24 April 1906 – 11 January 2001), was the youngest child of Grand Duke Konstantine Konstantinovich of Russia and his wife, Grand Duchess Elizabeth Mavrikievna. A great-granddaughter of Tsar Nicholas I of Russia, she was born in the Russian Empire and was a childhood playmate of the younger children of Emperor Nicholas II of Russia. She lost much of her family during World War I and the Russian Revolution. At age twelve, she escaped revolutionary Russia, fleeing with her mother and brother George to Sweden. She spent the rest of her long life in exile, first in Western Europe and from the 1950s in the United States.
ground_truth: "K.R."