In the spring of the year 1564, he made another journey abroad, when he presented to the Emperor Maximilian his book, entitled "Monas Hieroglyphica," printed at Antwerp the same year. He returned to England in the summer, producing several learned works, which showed his extraordinary skill in the mathematics. In 1571 he went to Lorraine, where, falling very ill, he was honoured with the solicitude of the Queen, who sent two of her physicians, and gave him many other proofs of her regard. Upon his return to England he now settled himself in his own house at Mortlake in Surrey, where he collected a noble library, and prosecuted his studies with great diligence. His collection is said to have consisted of more than four thousand books, nearly a fourth part of them manuscripts, which were afterwards dispersed and lost. This library, and a great number of mathematical and mechanical instruments, were destroyed by the fury of the populace in 1583, who, believing him to be a conjuror, and one that dealt with the devil, broke into his house, and tore and destroyed the fruit of his labours during the forty years preceding. On the 16th March 1575, Queen Elizabeth, attended by many of her court, visited Dr Dee's house to see his library; but having buried his wife only a few hours before, he could not entertain her Majesty in the way he wished. However, he brought out a glass, the properties of which he explained to his royal mistress, hoping to wipe off the aspersion, under which he had long laboured, of being a magician. In 1578 her Majesty being indisposed, Dee was sent abroad to consult with some German physicians about the nature of her complaint. But that part of his life in which he was most known to the world commenced in 1581, when his intercourse began with Edward Kelly. This man pretended to instruct him how to obtain, by means of certain invocations, an intercourse with spirits. Soon afterwards there came to England a Polish lord, Albert Laski, palatine of Siradia, a person of great learning. He was introduced to Dee by the Earl of Leicester, who was now the doctor's chief patron. Becoming acquainted, Laski prevailed with Dee and Kelly to accompany him to his own country. They went privately from Mortlake, embarking for Holland, from whence they travelled by land through Germany into Poland. On the 3d February 1584, they arrived at the castle of their patron, where they remained for some time. They afterwards visited the Emperor Rodolphe at Prague. On the 17th April 1585, Laski introduced them to Stephen, king of Poland, at Cracow; but this prince treating them very coolly, they returned to the emperor's court at Prague, from whence they were banished at the instigation of the Pope's nuncio, who represented them as magicians.