The first binoculars were built in December 1608 for the Assembly of the States General of the Netherlands by Hans Lippershey. He was a spectacle maker from Middleburg in Zeeland and had discovered that a convex lens and a concave lens could be combined to produce a magnified image of a distant object - a simple telescope. Lippershey offered his telescope to the States General on 2nd October 1608, and they requested a version to be used by both eyes, for military purposes. Three sets of binoculars (meaning roughly 'two eyes') were duly delivered but do not seem to have been a huge success with the military, perhaps because they would have had low magnification and poor image quality. Lippershey requested a patent on his invention but it was refused on the grounds that it was not sufficiently novel. Indeed there is some doubt as to whether Lippershey really was the first to combine two lenses into a telescope. Certainly by early 1609 small 'spyglasses', which we would call telescopes, were widely on sale in Paris. Binoculars however were seldom made because they required much more than twice as much work as a telescope, to manufacture two precisely matched pairs of lenses and fix them in accurate alignment.
Considering that lenses had been available for several centuries, it is somewhat surprising that no-one had discovered the telescope before 1608. Possibly the reason is that to obtain useful magnification the eyepiece lens needs to have a short focal length and thus a large amount of curvature, and lens-grinding technology was not capable of producing such lenses of sufficient quality to yield a clear image.