answers: about 1290
context: a glass sphere in half. As the stones were experimented with, it was slowly understood that shallower lenses magnified more effectively. Around 1286, possibly in Pisa, Italy, the first pair of eyeglasses were made, although it is unclear who the inventor was. The earliest known working telescopes were the refracting telescopes that appeared in the Netherlands in 1608. Their inventor is unknown: Hans Lippershey applied for the first patent that year followed by a patent application by Jacob Metius of Alkmaar two weeks later (neither was granted since examples of the device seemed to be numerous at the time). Galileo </s> known to have written on the magnifying properties of lenses. The development of the first eyeglasses took place in Northern Italy in the second half of the 13th century. Independently of the development of optical lenses, some cultures developed "sunglasses" for eye protection, without any corrective properties. Thus, flat panes of smoky quartz, were used in 12th-century China. Similarly, the Inuit have used snow goggles for eye protection. The first eyeglasses were made in Northern Italy, most likely in Pisa, by about 1290: In a sermon delivered on 23 February 1306, the Dominican friar Giordano da Pisa (ca. 1255–1311) wrote </s> on empirical knowledge gained from observing the effects of the lenses (probably without the knowledge of the rudimentary optical theory of the day). The practical development and experimentation with lenses led to the invention of the compound optical microscope around 1595, and the refracting telescope in 1608, both of which appeared in the spectacle-making centres in the Netherlands. With the invention of the telescope and microscope there was a great deal of experimentation with lens shapes in the 17th and early 18th centuries trying to correct chromatic errors seen in lenses. Opticians tried to construct lenses of varying forms of
question: when was the first pair of glasses made