Describing Hazel Shade's investigations in the Haunted Barn, Kinbote (in VN's novel Pale Fire, 1962, Shade’s mad commentator who imagines that he is Charles the Beloved, the last self-exiled king of Zembla) mentions an extraordinary episode from the history of Onhava University that took place in the year of grace 1876:
From Jane P. I obtained however a good deal of quite different, and much more pathetic information - which explained to me why my friend had thought fit to regale me with commonplace student mischief, but also made me regret that I prevented him from getting to the point he was confusedly and self-consciously making (for as I have said in an earlier note, he never cared to refer to his dead child) by filling in a welcome pause with an extraordinary episode from the history of Onhava University. That episode took place in the year of grace 1876. But to return to Hazel Shade. She decided she wanted to investigate the "phenomena" herself for a paper ("on any subject") required in her psychology course by a cunning professor who was collecting data on "Autoneurynological Patterns among American university students." Her parents permitted her to make a nocturnal visit to the barn only under the condition that Jane P. - deemed a pillar of reliability - accompany her. Hardly had the girls settled down when an electric storm that was to last all night enveloped their refuge with such theatrical ululations and flashes as to make it impossible to attend to any indoor sounds or lights. Hazel did not give up, and a few days later asked Jane to come with her again, but Jane could not. She tells me she suggested that the White twins (nice fraternity boys accepted by the Shades) would come instead. But Hazel flatly refused this new arrangement, and after a row with her parents took her bull's-eye and notebook and set off alone. One can well imagine how the Shades dreaded a recrudescence of the poltergeist nuisance but the ever-sagacious Dr. Sutton affirmed - on what authority I cannot tell - that cases in which the same person was again involved in the same type of outbreaks after a lapse of six years were practically unknown. (note to Line 347)
In 1876 Professor Andrey Beketov (1825-1902), the celebrated botanist and grandfather of the poet Alexander Blok (1880-1921), was elected Rector of the Imperial St. Petersburg University. In the penultimate line of his poem V golodnoy i bol'noy nevole ("In the hungry and sick slavery," 1909) Alexander Blok (who was born on Nov. 28, 1880, in the Rector's House of the University) mentions gospodne leto (the Summer of our Lord):
В голодной и больной неволе
И день не в день, и год не в год.
Когда же всколосится поле,
Вздохнет униженный народ?
Что лето, шелестят во мраке,
То выпрямляясь, то клонясь
Всю ночь под тайным ветром, злаки:
Пора цветенья началась.
Народ — венец земного цвета,
Краса и радость всем цветам:
Не миновать господня лета
Благоприятного — и нам.
Leto Gospodne ("The Year of Grace," 1927-1948) is the three-volume autobiographical novel by Ivan Shmelyov (1873-1950). Shmelyov's story Vinograd ("The Grape," 1936) brings to mind "Vinogradus," as Kinbote mockingly calls Gradus (Shade's murderer who contended that the real origin of his name should be sought in the Russian word for grape, vinograd, to which a Latin suffix had adhered, making it Vinogradus):
The Zemblan Revolution provided Gradus with satisfactions but also produced frustrations. One highly irritating episode seems retrospectively most significant as belonging to an order of things that Gradus should have learned to expect but never did. An especially brilliant impersonator of the King, the tennis ace Julius Steinmann (son of the well-known philanthropist), had eluded for several months the police who had been driven to the limits of exasperation by his mimicking to perfection the voice of Charles the Beloved in a series of underground radio speeches deriding the government. When finally captured he was tried by a special commission, of which Gradus was member, and condemned to death. The firing squad bungled their job, and a little later the gallant young man was found recuperating from his wounds at a provincial hospital. When Gradus learned of this, he flew into one of his rare rages--not because the fact presupposed royalist machinations, but because the clean, honest, orderly course of death had been interfered with in an unclean, dishonest, disorderly manner. Without consulting anybody he rushed to the hospital, stormed in, located Julius in a crowded ward and managed to fire twice, both times missing, before the gun was wrested from him by a hefty male nurse. He rushed back to headquarters and returned with a dozen soldiers but his patient had disappeared.
Such things rankle - but what can Gradus do? The huddled fates engage in a great conspiracy against Gradus. One notes with pardonable glee that his likes are never granted the ultimate thrill of dispatching their victim themselves. Oh, surely, Gradus is active, capable, helpful, often indispensable. At the foot of the scaffold, on a raw and gray morning, it is Gradus who sweeps the night's powder snow off the narrow steps; but his long leathery face will not be the last one that the man who must mount those steps is to see in this world. It is Gradus who buys the cheap fiber valise that a luckier guy will plant, with a time bomb inside, under the bed of a former henchman. Nobody knows better than Gradus how to set a trap by means of a fake advertisement, but the rich old widow whom it hooks is courted and slain by another. When the fallen tyrant is tied, naked and howling, to a plank in the public square and killed piecemeal by the people who cut slices out, and eat them, and distribute his living body among themselves (as I read when young in a story about an Italian despot, which made of me a vegetarian for life), Gradus does not take part in the infernal sacrament: he points out the right instrument and directs the carving.
All this is as it should be; the world needs Gradus. But Gradus should not kill kings. Vinogradus should never, never provoke God. Leningradus should not aim his peashooter at people even in dreams, because if he does, a pair of colossally thick, abnormally hairy arms will hug him from behind and squeeze, squeeze, squeeze. (note to Line 171)
"One highly irritating episode" reminds one of "an extraordinary episode from the history of Onhava University." Describing a conversation at the Faculty Club, Kinbote compares Gerald Emerald (a young instructor at Wordsmith University who gives Gradus a lift to Kinbote's rented house in New Wye) to a disciple in Leonardo's Last Supper. Grapes and Walnuts on a Table is an 1876 oil-on-canvas still life painting by Alfred Sisley (a British Impressionist artist, 1839-1899, active in France):

A few moments before the poet's death, Kinbote invites Shade to a glass of Tokay at his place and mentions a knackle of walnuts:
"Well," I said, "has the muse been kind to you?"
"Very kind," he replied, slightly bowing his hand-propped head. "exceptionally kind and gentle. In fact, I have here [indicating a huge pregnant envelope near him on the oilcloth] practically the entire product. A few trifles to settle and [suddenly striking the table with his fist] I've swung it, by God."
The envelope, unfastened at one end, bulged with stacked cards.
"Where is the missus?" I asked (mouth dry).
"Help me, Charlie, to get out of here," he pleaded. "Foot gone to sleep. Sybil is at a dinner-meeting of her club."
"A suggestion," I said, quivering. "I have at my place half a gallon of Tokay. I'm ready to share my favorite wine with my favorite poet. We shall have for dinner a knackle of walnuts, a couple of large tomatoes, and a bunch of bananas. And if you agree to show me your 'finished product,' there will be another treat: I promise to divulge to you why I gave you, or rather who gave you, your theme."
"What theme?" said Shade absently, as he leaned on my arm and gradually recovered the use of his numb limb.
"Our blue inenubilable Zembla, and the red-caped Steinmann, and the motorboat in the sea cave, and - "
"Ah," said Shade, "I think I guessed your secret quite some time ago. But all the same I shall sample your wine with pleasure. Okay, I can manage by myself now." (note to Line 991)