The modern style guitar that we think of today, with its classical look, style and appearance, with six strings and a sound that is instantly recognizable, is thought o have most likely descended from Spanish guitars, called either vihuela, or viola da mano. These instruments were popular during the 15th and 16 centuries, and had a distinct appearance that, whilst similar in many respects to a modern day guitar, owed more of its heritage to the lute, with its bulbous, curved body and backplate. However, the modern guitar owes much to these Spanish ancestors, and also to the guitar style instruments popular throughout the renaissance period.
The Spanish vihuela, whilst very popular, began to quickly fade from regular use as the more modern day style of guitar was being developed, and became more popular, and indeed by about the year 1576 the vihuela was all but a memory, with the guitar being the instrument of choice for those musicians who were in keeping with the modern climate and traditions. The Spanish guitar still owed much of its appearance and design to the lute instruments, although it is unclear whether it was also influenced by another guitar type instrument known as the oud, which was an Arabic instrument also being formed from a hollow body, a long neck, and strings, although these were generally plucked rather than strummed, creating quite a different sound - and one that is still very much traditional to eastern musical tradition.
The shape of the traditional Spanish guitar started to move away from the old style lutes and even the ouds, and became visually much more the style we see today, and it was this instrument which found a firm footing across the whole of Europe, with eastern countries sticking more to the oud, and thereby creating the difference in sound we hear today between eastern and western stringed music.
The Spanish guitar was a six stringed instrument, as are the guitars popular today, and one of the oldest examples of such a six string guitar style instrument is the mandolin, which was developed by a family of luthiers known as the Vinaccia family, and it is to these people that the mandolin heritage can be traced. Elsewhere in Europe, a six string guitar found in Naples has a label on it with the signature of the man who designed and built the instrument. It is this label dated 1779 which allows the history of six string guitars to be traced back at least this far in Italy, showing a rapid progression across Europe of this style of instrument.
Because of the popularity of these old guitars, and their importance in history, a vast number of false labels have been discovered, and museums and collectors have to be especially careful not to be fooled with fraudulent labels suggesting guitars are older than they really are. It certainly is true that the instrument has a long and easily traced history, but it is the guitar from Naples which has been confirmed as the oldest genuine surviving instrument of its type.
The style and shape of the guitar we see today were developed during the mid 19th century by a man named Antonio Torres Jurado, who was working as an instrument maker in Seville. For those who are familiar with the intricate design of a modern guitar, it was Torres, in conjunction with another instrument designer named Panormo from London, who demonstrated and established the fact that the strutting of fans led to far superior sound quality than the traditionally adopted transverse table bracing, and so the design of the modern guitar was born.