Although Galileo Galilei was a great astronomer, he didn't invent the telescope.A man named Hans Lipperhey invented the telescope. He was born in Wesel, Germany and made his home in Middleburg, part of the Zeeland province in the Netherlands. He was married there in 1594, and became a citizen in 1602. He was a spectacle-maker by trade.Many other people claim to have invented the telescope, but Hans Lipperhey is the only person documented to have applied for a patent for the device.

The Italians developed new glass-making techniques which were introduced to the Netherlands in the 1590's. These new techniques helped to bring about new ideas and innovations in the glass-making community and people started to experiment with different ways to combine lenses.Legend has it that it wasn't Hans himself, but his children who actually invented the telescope while they were playing.

Source: Monocular Telescope