According to Jains time is beginningless and eternal. During the 3rd / 4th phase of each time cycle, 24 Tirthankaras (spiritual guides) are born who propound the truth and reality of life. In the current time cycle, it can be said that Jainism started with Lord Adinath, the first tirthankar. The last tirthankar of the current time cycle was Lord Mahaveer, born in 599BC. All the teachings Jains follow at present are from him. Therefore, origin of Jainism is a relative term. For the current time cycle, Lord Adinath can be considered as the originator of Jainism, though from a practical point of view all the teachings Jains follow at present are originated from Lord Mahaveer and yet in future time cycles there will be other enlightened souls who will be considered as originators of Jainism.
It is analogous to asking what is the starting point of a circle. The answer is that wherever you start drawing the circle becomes the starting point.
Jainism is an independent philosophy. There is often a misconception that it is a branch of Hinduism which it is not. In general, the main difference lies in the concept of God. Whilst Hinduism is Henotheist (i.e. believing in a single God without denying existence of other Gods), it believes in a creator God. Jains on the other hand do not believe in a creator God. Nature, universe exists as per the natural laws and during certain time periods, enlightened souls are born who themselves achieve liberation and show the path of liberation to others too. Therefore, when Jains pray they are not asking for any boons, but are seeking to gain the same guna (qualities) as their enlightened idols. They venerate the idols to become ideal souls.
The term Jainism is relatively a recent title. Etymologically, it derives its name from Jin (to conquer). That may seem counter intuitive as Jains strongly adhere to the principle of non-violence, so conquer one’s enemies seems bizarre. However, it refers to conquer one’s inner enemies such as anger, pride, deceit and greed.
Before it was known as sramana culture. What was the main characteristics of people who were following the sramana culture? They were peace-loving vegetarians, believed in the cosmos and beyond cosmos (aloka), various life forms, existence of soul, karma and reincarnation.