There have been instruments like the guitar for at least 5,000 years. The guitar may have come from older instruments known as the sitara from ancient India and central Asia. The oldest known picture of a guitar-like instrument is a 3300 year old stone carving of a Hittite bard.The oldest guitar-like instrument that is still complete is the “Warwick Gittern” in the British Museum. It belonged to Elizabeth I of England and probably to her father Henry VIII before it was given to her. It is about 500 years old.
The design of the modern guitar began with the Roman cithara. The cithara was brought by the Romans to Hispania (Spain) around 40 AD. In
the 8th century the Moors brought the four-stringed oud into Spain. The introduction to the oud caused changes to the design of the cithara. In other parts of Europe, the six-string Scandinavian lut (lute) became popular wherever the Vikings had been. By 1200 AD, there were two types of the four string “guitar”: the guitarra morisca (Moorish guitar) from Spain which had a rounded back, wide fingerboard and several soundholes, and the guitarra latina (Latin guitar) which was more like the modern guitar with one sound hole and a narrower neck.
The Spanish vihuela, of the 16th century, was another instrument similar to the guitar. It had lute-style tuning and a body that was like a guitar. The vihuela was only popular for a short amount of time. It is not known whether it was simply a design that combined features of the oud and lute or a transition from the Renaissance instrument to the modern guitar.
The Vinaccia family from Naples, Italy were famous mandolin makers. It is thought that they also made the oldest six-string guitar that still exists. There is a guitar built that was signed and dated 1779 on the label by Gaetano Vinaccia (1759 – after 1831) Although there are many fakes that have dates on them from that time, this guitar is believed by experts to be genuine (real).
The guitar’s design was improved (made better) by the famous Spanish luthier, Antonio Torres Jurado (1817-1892) and by Louis Panormo of London.
The electric guitar was made by George Beauchamp in 1936. Beauchamp co-founded a company called Rickenbacher to make guitars. However, Danelectro was the first to produce electric guitars for the public to use. (Source https://simple.wikipedia.org/wiki/Guitar#History)