The oven enabled humans to cook their food and heat their homes, as well as make pottery and bricks. Ovens evolved over many years and there are now many varieties of ovens, each having been invented for a different purpose.
The oven as it is known today evolved a lot over time. The first ovens were found in Central Europe and date to 29,000 BCE. These "ovens" were actually more like pits on which ancient humans placed food, often wrapped in leaves and covered with earth and are more commonly known as hearths. Almost all ancient homes had a hearth, which was used for heating and cooking. These, as well as kilns, were also used for making pottery and bricks. Ovens used by the ancient Egyptians, Romans, Greeks, and Jews were usually made of stone or brick and were fueled with wood and were used mostly for baking bread. The Greeks are credited with creating the first front-loading oven; they also developed baking as a trade and profession.
During the Middle Ages, the Europeans used fireplaces and cauldrons similar to the Dutch oven, but afterward, the oven evolved significantly. Wood, iron, coal, gas, and electric ovens were invented, each with a different purpose. The first oven to be recorded was built of brick and tiles in France in the late 1400's. Around 1728, cast-iron ovens started to be made on a large scale. Then, in 1735, a man named François Cuvilliés invented the Castrol stove - also known as the Stew stove. His design was innovative because it was enclosed, keeping the smoke inside.
Toward the end of the 18th century, Benjamin Thompson created an iron stove that had only one fire source but four stove tops that could be controlled separately. This innovative design also acted as a heat source, but it was too large for many kitchens. In the 1800's, James Sharp patented the first gas oven. The first recorded use of a gas oven for cooking was in 1802 by a man named Zachaus Winzler. These gas ovens did not become popular until the end of the century, when they started to be mass manufactured. In 1892, shortly after the introduction of electricity in the home, the first electric oven was developed. One of the first models was made by a Canadian named Thomas Ahearn.
In the 1900's, an engineer named Percy LeBaron Spencer was researching microwave-producing magnetrons when he discovered that microwaves could cook food quicker than heat. Eight years later, the company he worked for - Raytheon Corporation - produced and sold its first commercial microwave oven, and followed with its first domestic microwave oven. The domestic microwave oven took some time to catch on as it was expensive and many people feared radiation. Today, a variety of ovens exist - gas, electric, wood - with the microwave being one of the most common while wood-fired ovens are now the most expensive.