Archytas of Tarentum and His Flying Pigeon - 400 years BC
One of the first mechanical toys ever created was the flying pigeon of Archytas of Tarentum. His toy was wooden and propelled on a wire by escaping steam. Accordingly to Aristotle the same guy invented also a rattle intended to amuse infants. He was one of the pioneers of automata and mechanical toys.
Ancient Greek, Egyptian and Romain - 3rd Century BC
The first mechanical toys were big and mystical, usually shown in fairs in Europe. These toys were hand-built by crafsters and usually powered by pneumatic power, wind or water. They have been so impressive and realistic that the church was quick to label them "instruments of the devil".
Real-size animated statues have been used in ceremonies by Anicent Greeks.
About the same time Ctesibius made a singing blackbird that drank water and moved.
16th Century - Leonardo da Vinci Mechanical Lion
There hasn't been any notable development in mechanical toys for more than 1500 years, perhaps because humanity was too engaged in wars. Bright persons like Leonardo da Vinci and Galileo Galilei had to come to the scene to get the things moving.
Leonardo made a mechanical lion as a present for king Louis XII. The lion could walk and open its chest to reveal a cluster of lilies. You can see a video of his lion here.
At the same time Galileo Galilei was making simple mechanical toys as a kid. Reports say that all of them worked.
17th and 18th Centuries - Clockwork Gears
The end of the Renaissance is the time when the clockwork gears began to power the mechanical toys. These gears allowed the toys to perform very elaborate and amazing movements and tasks.
Some toys were able to play musical instruments or write whole sentences.
Some toys, especially mechanical monkeys, were used in advertising of cigarettes and tea and were very popular.
In 1738 Frenchman Jacques de Vaucanson invented one of the first mechanical robots - a duck that was able to eat wheat, drink and excrete. Vaucanson made also amazing flute and tabor players with repretoires of different tunes. The spectators could actually feel the breat coming from the lips of the players. Jacques de Vaucanson is often regarded as the greatest mechanical toy crafter of all times.
Nearly the same time Pierre Jaquet-Doz created The Writer, The Draftsman and The Musician - 3 of the most amazing automata ever created. His toys still exist in the museum of Art and History in Switzerland.
19th Century - American Clockwork Toys
If the toys of the previous two genial mechanics have blown your mind, prepare for even more. The 19th century is perhaps the golden age of the mechanical toys. First, this is the time of Americal clockwork toys. All kind of dancing figures, steamboats and trains driven by clock mechanisms were produced commercially. However these toys costed between $2.50 and $4.50 which was a lot for that time.
Around the end of the century the European toy makers focused on simpler and cheaper mechanical toys driven by spring (we know them today as wind-up toys) or friction (cam and crank toys).
19th Century is also the time of the famous Euphonia. This toy had a movable replica of human face and was able to sing, laugh, ask and answer questions. The machine was inspected and it was proven that the sounds are really produced by the gears in it.
The end of the 19th century was the time of mechanical toy banks. These toys work when a coin is deposited in their bank. Then the weight of the coin or pulling a lever sets the toy in action.
Spring-driven wind-up toys are in their apogee. First produced mostly in Europe and imported to the USA, in the beginning of 20th century they are already manufactured in the USA as well. These toys remain very popular to the end of World War II.
After the World War II the cheaper plastic toys - both mechanical and electronic became far more popular and made the iron wind-up toys obscure. After that, you perhaps remember, the RC toys and video games became the mainstream entertainment tool for kids.
Of course, although not as popular, mechanical toys are still alive and kicking even today. Otherwise you wouldn't be reading this article to the end ;)