Chinese martial arts, as with all fighting styles have been around since pre-history; unarmed combat has been practiced by every culture, and by every people, however, what is unique about China is two things.
1) They are the only culture in the world that has existed consistently for 4,000 years. For example, genetically speaking, modern day semitic people, in reality, are identical to their ancestors in practically every way, so much so that even appearance wise, the peoples of the Arabian peninsula have not truly changed at all. HOWEVER, culturally, the middle east has gone through cultures, like the different seasons of the year. In a given time period they engaged in orgies and child sacrifice, in another time period they were philosophical and ethical, then it was back to the orgies, then it was back to being philosophical again. In terms of their "core" mindset, the Chinese for example have believed that lazy people are worthless, for 4,000 years. If you talk to a modern Chinese man and ask him "are lazy people worthless?" He would quickly answer either "yes" OR, that it is preferable to work ultra hard, all the time. If you traveled back in time to Han era China you would encounter the exact same mentality; although their surroundings may have changed, the Chinese are not at all different, they are still the same as they were 4,000 years ago. What does this have to do with Kung Fu? Well, because they have been consistently civilized city dwellers for most of their cultural life, they have been plagued by the problems big city life has, for a full 4,000 years. Problems ranging from work related stress, to crime, crime having plagued China, almost from the fall of the Han. This, combined with widespread corruption and poverty made it so that most Chinese could not even afford to buy weapons for self protection, thus, too poor, they had no choice but to rely solely on their hands.
2) The ethics of Buddhism and Daoism, which discourage killing.
See in other cultures around the world, widespread crime in cities did not become a problem until only recently, China, on the other hand has suffered from criminal activity for nearly 2,000 years. Even though tyranical, even though abusive sometimes, part of the reason the Communist government of Mao Zedong was able to take power, is because he promised to end crime, naturally, "Chairman Mao" received the support of a lot of Chinese who were fed up with centuries of crime. By and large the Communist party kept its promise, and cleaned up the streets; China's criminals were forced to flee to Hong Kong.
What I am trying to say is, in most cultures the world over, the moment some war was over, most people prefered to abandon weapons, and knowledge of war and just go back to their daily lives. Also because most of the world was relatively crime free, they were not plagued by it the way the Chinese were. The truth is, in days past ancient people, and in some cases midieval people were more ethical than modern; again, crime was basically unheard of, it has been said by British critics of the industrial revolution, that one of the byproducts of industrialization, has been crime. Because industry has the capacity to "feed the greed," and because it is a machine with so many legal entanglements, once a selfish bastard becomes powerful, they are not as easy to remove. In ancient and midieval times, if a selfish bastard became powerful, all it would take to get rid of him was an angry mob with pitch forks and torches.
Now, you need to hire an attorney, you need to talk to your congressman, you need to engage in court battles, you need to rally people also victimized by that person the point I am trying to make here is, the modern day industrial society works very, very hard, to keep bad people protected and out of harm's way. In olden times you HAD to be nice, you had to be ethical, or, an angry mob would kill you. As technology progressed, and industry took over, the tighter resource control by smaller and smaller groups of individuals meant that if you took a "pitch forks and torches" mob, it meant that change, would mean months without work, and without food.
China, suffered from these problems, long before all other cultures did; industry was in fact invented in China, not Britain, HOWEVER, it was the British, who spread industry all over the world, and with it, all its problems.
The combination of history, and the ethics that govern Chinese philosophy contributed to the development of Kung Fu.
Now, as to the birth, the inventor of Kung Fu was a southern Indian Tamil Prince named Bodhidharma, Daruma for short. Like all Tamil royals, Daruma received an education ranging from the philosophies of Hinduism, to advanced mathematics, I need to point out that Calculus was invented in India, it was NOT invented by Leibnitz. However, it was a primitive form of it, roughly the equivalent of modern day "pre-Calc" rather than college level stuff. I also need to point out though that Daruma likely did his Calculus homework with an Abacus, not a slide ruler, or calculator. An Abacus is very accurate, but it is extremely difficult to use well. Why is Daruma's knowledge of math important?
Because, martial arts is governed by geometry and physics, namely, how physics apply to the geometry of in what position muscles are strongest and weakest, and from what stance. Additionally, Daruma was a Yogi, thanks to his mental training he was able to literally walk to China, across the jungles of India, over the bitter cold Himalayas, and across the gobi, upon reaching China, Daruma was harassed by bandits although he successfully fended them all of them off obviously.
He sat down in a cave where he meditated for 9 years, developing what would become Shaolin Kung Fu entirely in his head. This is not impossible; some men have a highly developed imagination, and many even developed complex things entirely from their imagination. Nicola Tesla mentally invented alternating current; he had "built" the system for AC, completely in his head. Alternating current is the electricity that powers the computer you are using to read this; what you are benefiting from now, was the product of a man's imagination. Of course, to be effective, imagination needs to be backed up by solid education, which Tesla had. Daruma, very much, had the necessary background to invent a new fighting style.
Another thing I need to point out, is that like all Tamil royals, during his days as a prince, Daruma learned how to wrestle. Indian style wrestling is highly effective; the Great Gama of India, defeated the best grapplers from all over the world. A lot of the techniques used in modern day American High School and College level wrestling, were techniques originally taught to his vanquished American opponents by Gama. In other words Daruma was well aware of how human bodyweight behaved from first hand experience in ADDITION to having had a solid math education, an awareness of angles, and geometry.
As if that wasn't enough credentials to give to Kung Fu, the martial art Daruma invented has been tested in a culture plagued by violent crime, over a period of 1,450 years, roughly. Make no mistake; assuming you are competently trained, and remember to do your meditation, Kung Fu works.
If you want to get better results from meditation I recomend you use a lot of Dragon's Blood incense.
Dragon's blood incense is said to posses soul purifying properties, and it is the best kind of incense to burn while practicing Kung Fu. If you want, you can try something called "incense fumigation." Basically, you light four sticks of incense, inside a small tent, and meditate. What does incense fumigation do?
According to the native americans, the smoke of certain herbs, certain plants, in this case incense, when inhaled at close range, has the power to purify the soul. If you want to get stronger in your martial arts faster, I recomend you use Dragon's Blood.