Task: Question Generation
Input (English): Passage: The main sources for the story told in Busenello's libretto are the Annals of Tacitus; book 6 of Suetonius's history The Twelve Caesars; books 61–62 of Dio Cassius's Roman History; and  an anonymous play Octavia (once attributed to the real life Seneca), from which the opera's fictional nurse characters were derived. The main story is based on real people  and   events. According to the analyst Magnus Schneider, the character of Drusilla was taken from Girolamo Bargagli's 16th-century comedy The Pilgrim Woman.Busenello condensed historical events from a seven-year period (AD 58 to AD 65) into a single day's action, and imposed his own sequence. He was open about his intention to adapt history for his own purposes, writing in the preface to his libretto that "here we represent these actions differently." Thus he gave his characters different attributes from those of their historical counterparts: Nerone's cruelty is downplayed; the wronged wife Ottavia is presented as a murderous plotter; Seneca, whose death in reality had nothing to do with Nerone's liaison with Poppea, appears as more noble and virtuous than he was; Poppea's motives are represented as based on genuine love as much as on a lust for power; the depiction of Lucano as a drunken carouser disguises the real life poet Lucan's status as a major Roman poet with marked anti-imperial and pro-republican tendencies.The libretto has survived in numerous forms—two printed versions, seven manuscript versions or fragments, and an anonymous scenario, or summary, related to the original production. One of the printed editions relates to the opera's 1651 Naples revival; the other is Busenello's final version published in 1656 as part of a collection of his libretti. The manuscripts are all from the 17th century, though not all are specifically dated; some are "literary" versions unrelated to performances. The most significant of the manuscript copies is that discovered in Udine, Northern Italy, in 1997 by Monteverdi scholar Paolo Fabbri. This manuscript, according to music historian Ellen Rosand, "bristles with the immediacy of a performance", and is the only copy of the libretto that mentions Monteverdi by name. This, and other descriptive details missing from other copies, leads Rosand to speculate that the manuscript was copied during the course of a performance. This impression is reinforced, she says, by the inclusion of a paean of praise to the   singer (Anna di Valerio according to Schneider) who played the role of Poppea. Although its dating is uncertain, the manuscript's affinity with the original scenario has led to speculation that the Udine version may have been compiled from the first performance.
Output (English): What year was the manuscript that music historian said was something that "bristles with the immediacy of a performance" discovered?