Question: What century did a notable subjective idealist live in?

Knowledge 1: Idealism
Subjective idealists like George Berkeley are anti-realists in terms of a mind-independent world, whereas transcendental idealists like Immanuel Kant are strong skeptics of such a world, affirming epistemological and not metaphysical idealism. Thus Kant defines idealism as "the assertion that we can never be certain whether all of our putative outer experience is not mere imagining". He claimed that, according to idealism, "the reality of external objects does not admit of strict proof. On the contrary, however, the reality of the object of our internal sense (of myself and state) is clear immediately through consciousness."  However, not all idealists restrict the real or the knowable to our immediate subjective experience. Objective idealists make claims about a transempirical world, but simply deny that this world is essentially divorced from or ontologically prior to the mental. Thus Plato and Gottfried Leibniz affirm an objective and knowable reality transcending our subjective awareness—a rejection of epistemological idealism—but propose that this reality is grounded in ideal entities, a form of metaphysical idealism. Nor do all metaphysical idealists agree on the nature of the ideal; for Plato, the fundamental entities were non-mental abstract forms, while for Leibniz they were proto-mental and concrete monads. [SEP] Knowledge 2: Idealism
The earliest extant arguments that the world of experience is grounded in the mental derive from India and Greece. The Hindu idealists in India and the Greek Neoplatonists gave panentheistic arguments for an all-pervading consciousness as the ground or true nature of reality. In contrast, the Yogācāra school, which arose within Mahayana Buddhism in India in the 4th century CE, based its "mind-only" idealism to a greater extent on phenomenological analyses of personal experience. This turn toward the subjective anticipated empiricists such as George Berkeley, who revived idealism in 18th-century Europe by employing skeptical arguments against materialism.
Knowledge 1: Idealism
Subjective idealists like George Berkeley are anti-realists in terms of a mind-independent world, whereas transcendental idealists like Immanuel Kant are strong skeptics of such a world, affirming epistemological and not metaphysical idealism. Thus Kant defines idealism as "the assertion that we can never be certain whether all of our putative outer experience is not mere imagining". He claimed that, according to idealism, "the reality of external objects does not admit of strict proof. On the contrary, however, the reality of the object of our internal sense (of myself and state) is clear immediately through consciousness."  However, not all idealists restrict the real or the knowable to our immediate subjective experience. Objective idealists make claims about a transempirical world, but simply deny that this world is essentially divorced from or ontologically prior to the mental. Thus Plato and Gottfried Leibniz affirm an objective and knowable reality transcending our subjective awareness—a rejection of epistemological idealism—but propose that this reality is grounded in ideal entities, a form of metaphysical idealism. Nor do all metaphysical idealists agree on the nature of the ideal; for Plato, the fundamental entities were non-mental abstract forms, while for Leibniz they were proto-mental and concrete monads. [SEP] Knowledge 2: Sino-Tibetan relations during the Ming dynasty
Elliot Sperling, a specialist of Indian studies and the director of the Tibetan Studies program at Indiana University’s Department of Central Eurasia Studies, writes that "the idea that Tibet became part of China in the 13th century is a very recent construction." He writes that Chinese writers of the early 20th century were of the view that Tibet was not annexed by China until the Manchu Qing dynasty invasion during the 18th century. He also states that Chinese writers of the early 20th century described Tibet as a feudal dependency of China, not an integral part of it. Sperling states that this is because "Tibet was ruled as such, within the empires of the Mongols and the Manchus" and also that "China's intervening Ming dynasty ... had no control over Tibet." He writes that the Ming relationship with Tibet is problematic for China’s insistence of its unbroken sovereignty over Tibet since the 13th century. As for the Tibetan view that Tibet was never subject to the rule of the Yuan or Qing emperors of China, Sperling also discounts this by stating that Tibet was "subject to rules, laws and decisions made by the Yuan and Qing rulers" and that even Tibetans described themselves as subjects of these emperors.
Knowledge 1: Jean Delville
Jean Delville (19 January 1867, Leuven – 19 January 1953, Forest, Brussels) was a Belgian symbolist painter, author, poet, polemicist, teacher, and Theosophist. Delville was the leading exponent of the Belgian Idealist movement in art during the 1890s. He held, throughout his life, the belief that art should be the expression of a higher spiritual truth and that it should be based on the principle of Ideal, or spiritual Beauty. He executed a great number of paintings during his active career from 1887 to the end of the second World War (many now lost or destroyed) expressing his Idealist aesthetic. Delville was trained at the "Académie des Beaux-arts" in Brussels and proved to be a highly precocious student, winning most of the prestigious competition prizes at the Academy while still a young student. He later won the Belgian Prix de Rome which allowed him to travel to Rome and Florence and study at first hand the works of the artists of the Renaissance. During his time in Italy he created his celebrated masterpiece "L'Ecole de Platon" (1898), which stands as a visual summary of his Idealist aesthetic which he promoted during the 1890s in his writings, poetry and exhibitions societies, notably the "Salons d'Art Idéaliste". [SEP] Knowledge 2: The Crow and the Pitcher
The fable is made the subject of a poem by the first century CE Greek Poet Bianor, was included in the 2nd century fable collection of pseudo-Dositheus and later appears in the 4th -- 5th - century Latin verse collection by Avianus. The history of this fable in antiquity and the Middle Ages is tracked in A.E. Wright's Hie lert uns der meister: Latin Commentary and the Germany Fable.

Answer: 18th