Johannes Lippershey developed the binocular at the same time that he created the monocular telescope. In fact, Lippershey’s binoculars were simply two of his monocular telescopes fixed together. Just like their monocular cousins, early binoculars were unwieldy and not ideal for spying. This didn’t stop the Netherlands military, however, from purchasing three pairs for 900 florins, approximately $1000 each today.
Use of binoculars was not widespread until the 1800s when attention was refocused on their design. At that time, new attempts were made to coordinate 2 monoculars into a single instrument.