Buddhism is a nontheistic religion or philosophy that encompasses a variety of traditions, beliefs and spiritual practices largely based on teachings attributed to Gautama Buddha, commonly known as the Buddha ("the awakened one"). Buddhism is now part of the lives of many people with its meditation techniques used in secular settings, from mindfulness courses in the Houses of Parliament to stillness classes in schools.
Spread of Buddhism/Popularity
Buddhism was spread mostly by mouth. They had the 4 noble truths; Life is full of suffering, suffering is caused by desire, the way to overcome suffering is to overcome desire, to overcome desire you must follow the enlightened path. Today, Buddhism is found in Thailand, Sri Lanka, Myanmar, Cambodia, Laos, Japan, China, etc, and in some parts of India, Pakistan, Bangladesh and Nepal, also in the European countries and the USA. It is believed that the Buddhist population of the world is over 500 million.
Hinduism has no original founder or text, which makes it a very complex religion. The Universe played a vital key in Hinduism, as well as Brahman, who's like a many faced god. They believed in the afterlife.
Spread of Hinduism/Popularity
The spread of hunduism came from the travel and talk of merchants to other nearby countries. U.S. Hindu population is estimated at about 1.2 million--a tiny fraction of the 800 million Hindus worldwide.
People argue that Confucius was the wisest person to live, next to Buddha and Socrates. He never wrote down his sayings. The ruler was supposed to provide a good structural government and in return he'd be respected.
Spread of Confucianism/Popularity
Confucianism was popular in China and eventually spread to Japan, Korea and Vietnam. It was spread through the Chinese influence at the time. Today, Confucianism is still practiced in China, the Koreas and Vietnam.
Legalism was founded by Hanfeizi. He believed that man was bound to be bad, being feed with greed and desires. He practiced strict punishments and emphasized laws
Spread of Legalism/Popularity.
Legalism was forced into many parts of China, where it remained. It was eventually hated by the people and gotten rid of, but still the basis of many governmental thoughts.
The founder of Daoism is Laozi. He wrote the way of virtue and pushed for harmony with nature. He tried to end fights between cultures and didn't like traditional government. He was all about non-violence.
Spread of Daoism/ popularity
Daoism spread mostly across China, Korea, Japan, and many other parts of Asia. It was the followers that helped spread Daoism. Today Daoism is mainly practiced in China and Taiwan. It has also spread to other parts of Asia and even around the world.
There are about 20 million followers world wide--most of them living in Taiwan. About 30,000 North Americans practice Daoism. The main thing that keeps Daoism popular is its flexibility, it's more of a philosophy than a religion.