The History of the Clarinet 
About 2700 B.C., the Egyptians created an instrument called the zummara (sometimes referred to as the memet). The zummara was a single-reed instrument, much like the modern day clarinet, but it had a double bore like the double-reeded Greek instrument aulos. The zummara’s two pipes were parallel so that with each finger the player covered two holes, one on each pipe. The pipes were said to be out of tune with each other and produced a very dissonant beating sound.
In India, there was an instrument people now call the double-clarinet but in India it was called the pungi or the magudi. The difference between this instrument and the zummara was that the reed was enclosed in a wooden chamber and the left-hand pipe was drone, and the right-hand pipe was melodic.
Single reed instruments of this type have been found in many cultures throughout the world, as it is a simple way of producing sound. The reeds are called idioglot reeds and are cut out of part of the instrument that is placed inside the mouth to sound. A simple way of reconstructing one of these idioglot reeds is to cut a small triangular slit in a straw, when this is placed in the mouth it produces a buzzing sound. Instruments with these idioglot reeds are first mentioned in dictionaries in France in the Sixteenth century (for example Estienne (1511)) and are described in more detail in the Seventeenth Century treatises of Mersenne and Trichet.
The man universally credited for actually inventing, or making, the clarinet was Johann Christoph Denner (1655-1707) with the help of his son, Jacob, of Nuremberg, Germany. J.C. Denner was well-known and well-respected for the high quality woodwind instruments he made. Denner was said to have a creative mind; he toyed with the instruments he so finely crafted and it would seem the clarinet was the result of such tinkering. There is no documented proof that Denner alone developed the clarinet since two of his contemporaries, Klenig and Oberlender, also made clarinets.
However, it must also be mentioned that (apart from a single instrument at Berkley whose attribution is much disputed) there are no extant clarinets by J.C.Denner, only chalumeaux.
Scholars first believed the clarinet was developed around 1690, but further research has lead scholars and music historians to believe it was developed around 1701-1704. It is also believed the clarinet was first called a mock trumpet. There is a music book discovered by a scholar, Thurston Dart, for mock trumpet which was published in 1698, and this was followed by three similar volumes throughout the next decade. Doubt still remains about who made the clarinet and how.
The accepted hypothesis is that Denner crafted the clarinet, and he did so sometime around 1700. J.G. Doppelmayr, a contemporary of Denner, wrote a Report on the Mathematicians and Artisans of Nuremberg in 1730, twenty-three years after Denner’s death. The report indicates Denner developed the clarinet a little after 1700. Before this historical text was discovered, historians and scholars only had a piece written in 1778 by C.G. Murr, "Description of the Distinguished Features of Nuremberg," wherein Murr wrote that Denner created the clarinet in 1690.
What made the clarinet a clarinet was Denner's great improvement to the old chalumeau. The usual material used for early examples of both instruments is boxwood (a common material in instrument making) with a heteroglot reed (that is separate to the instrument)tied to the upper side of the mouthpiece therefore vibrated by the upper lip . To change the chalumeau to a clarinet he added a 'speaker key' (also known as the register key) causing the instrument to over-blow , creating a new and higher register for the instrument. This register is known as the clarino register (a reference to a style of trumpet playing) and is thought to be the origin of the name of the instrument. Many modern clarinettists still refer to the overblown register of the clarinet as the clarino register, and to the lower register as the chalumeau.
Acoustically the clarinet acts like a closed cylindrical tube and overblows at the twelfth. He also equipped it with a bell by enlarging the bore.The mouthpiece and barrel joint are made in one piece and, with Denner's additional key the earliest clarinets are two-keyed instruments. Extant chalumeaux have single keys at the front of the instrument.
The Clarinet's Early Days 
There is no mention of the name clarinet until 1690, right after Denner made the first playable clarinet. In this year, the Graf (Duke) of Gronsfeld in Nuremberg ordered two clarinets from Jacob Denner for the use of his musicians. In 1712, four clarinets that were made out of boxwood were bought by the Nuremberg Town band (Ratsmusik). Since Denner worked in Nuremberg and that’s where they first appeared in the band, it is said that Denner gave the instrument its name.
History of the clarinet from 1680-1751 
The history of the clarinet is a long history beginning in 1690. During that year a man named Johann Cristoph Denner invented the clarinet. These clarinets only had two keys that were mostly made from brass along with the springs. The clarinet however was made from boxwood, plum, ebony, ivory or pear. Around 1700 he added the register key to his instrument. In 1740 a third key was added ableing the players to play low E. Nine years later a man named Rameau uses the clarinet in his opera in Paris. Shortly after in 1750 Barthold Fritz added the 4th 5th key to the clarinet. The clarinet is introduced to London by Bach in 1751.