Galileo found a better use for a weapon of war!
Give the man a Nobel Peace Prize!!!
Same with Newton and the 'Newtonian' Reflector.
He didn't invent the reflecting telescope. James Gregory registered the design as a 'Gregorian' in 1663 but none were actually built until Robert Hooke made one in 1673.
But we credit Newton for the reflecting telescope because he made the first actual working model based on Gregory's idea in 1668 but vastly improved on it and made it popular.
In 1672 Cassegrain made his own design too.
The years 1663 through to 1673 were certainly a busy time for building and designing of telescopes!
Articles regarding the principles of Refractors and Reflectors have been around since the 11th century!