Instructions: In this task, you're given passages that contain mentions of names of people, places, or things. Some of these mentions refer to the same person, place, or thing. Your job is to write questions that evaluate one's understanding of such references. Good questions are expected to link pronouns (she, her, him, his, their, etc.) or other mentions to people, places, or things to which they may refer. Do not ask questions that can be answered correctly without understanding the paragraph or having multiple answers. Avoid questions that do not link phrases referring to the same entity. For each of your questions, the answer should be one or more phrases in the paragraph, and it should be unambiguous.
Input: Passage: On 21 January 1818, Friedrich married Caroline Bommer, the twenty-five-year-old daughter of a dyer from Dresden. The couple had three children, with their first, Emma, arriving in 1820.  Physiologist and painter Carl Gustav Carus notes in his biographical essays that marriage did not impact significantly on either Friedrich's life or personality, yet his canvasses from this period, including Chalk Cliffs on Rügen—painted after his honeymoon—display a new sense of levity, while his palette is brighter and less austere. Human figures appear with increasing frequency in the paintings of this period, which Siegel interprets as a reflection that "the importance of human life, particularly his family, now occupies his thoughts more and more, and his friends, his wife, and his townspeople appear as frequent subjects in his art."Around this time, he found support from two sources in Russia. In 1820, the Grand Duke Nikolai Pavlovich, at the behest of his wife Alexandra Feodorovna, visited Friedrich's studio and returned to Saint Petersburg with a number of his paintings, an exchange that began a patronage that continued for many years. Not long thereafter, the poet Vasily Zhukovsky, tutor to Alexander II, met Friedrich in 1821 and found in him a kindred spirit. For decades Zhukovsky helped Friedrich both by purchasing his work himself and by recommending his art to the royal family; his assistance toward the end of Friedrich's career proved invaluable to the ailing and impoverished artist. Zhukovsky remarked that his friend's paintings "please us by their precision, each of them awakening a memory in our mind."Friedrich was acquainted with Philipp Otto Runge, another leading German painter of the Romantic period. He was also a friend of Georg Friedrich Kersting, and painted him at work in his unadorned studio, and of the Norwegian painter Johan Christian Clausen Dahl (1788–1857). Dahl was close to Friedrich during the artist's final years, and he expressed dismay that to the art-buying public, Friedrich's pictures were only "curiosities". While the poet Zhukovsky appreciated Friedrich's psychological themes, Dahl praised the descriptive quality of Friedrich's landscapes, commenting that "artists and connoisseurs saw in Friedrich's art only a kind of mystic, because they themselves were only looking out for the mystic... They did not see Friedrich's faithful and conscientious study of nature in everything he represented".During this period Friedrich frequently sketched memorial monuments and sculptures for mausoleums, reflecting his obsession with death and the afterlife; he even created designs for some of the funerary art in Dresden's cemeteries. Some of these works were lost in the fire that destroyed Munich's Glass Palace (1931) and later in the 1945 bombing of Dresden.
Output:
What is the full name of the person whose assistance toward the end of Friedrich's career proved invaluable to the ailing and impoverished artist?