What is known about enlightenment before the lifetime of the Buddha? Are there any claims that he was the first?

In modern times, Eckhart Tolle reports spontaneous awakening as a result of a sudden realisation that came out of intense suffering. As far as I am aware he was uninfluenced by Buddhism and underwent none of its training or techniques.

There are different types of realisations.Which one he went through I don’t know.

I understand that the Buddha sat under a tree "until he was enlightened". This suggests to me that he knew of the phenomenon beforehand.

There were many Buddhas before Gautam Buddha. And there is a Buddha yet to come.Buddha shows us the path , makes us understand it , himself demonstrates it. But that doesn’t mean a Buddha takes a lesson from another Buddha. He himself discovers it.

Shakyamuni Buddha was not the first. In the Diamond Sutra, Shakyamuni Buddha said:

...before I met Dipankara Buddha, I had made offerings to and had been attendant of all 84,000 million Buddhas...

Gautama Buddha had various teachers in using different paths to seek his spiritual goal, but in each case he found those other ways defective. He wished to find a way to end the suffering of all beings, so after trying those other paths, he sat under the Bodhi Tree with the firm intention to not get up until he had found what he was looking for. And he succeeded.

There are different degrees of enlightenment, and there are different ways of describing the stages, so it is hard to compare, but the Buddha’s enlightenment is recognized by his followers as being the most profound—certainly more profound than that of Eckhart Tolle, based upon Tolle’s description of his. This is not a denigration of Tolle. It’s just a recognition that there are differences in attainments.

Enlightenment is a potential of all beings, and there are many paths to reach it. In Buddhism there are many Buddhas spoken of, who came before Gautama Buddha, and some that will come after him. As well, there are enlightened Bodhisattvas and Mahasattvas. In other spiritual traditions, there are many enlightened beings spoken of as well.

The Buddha had to make his own way forward and he taught his followers so that they could find their way to enlightenment too. It’s easier to succeed if you have a teacher, but it’s not necessary. This is an important point. The Buddha found his way—finally—without a teacher.

However, without a qualified teacher there are many pitfalls and even danger that one might succumb to, without the wisdom of a guide. The Buddha succeeded, but would we have known of him if he hadn’t? There are presumably many other enlightened beings throughout history that did not teach, and who had no teacher to recognize their attainments. What if the Buddha had never shared his accomplishment with others—would he still have been known? Perhaps he would have been seen as just a crank mumbling about gibberish, and quickly forgotten.

See: “A Life of Buddha” by Asvaghosha Bodhisattva, Sacred Books of the East, Edited by Max Müller, Vol. XIX, 1968

And: Manjushri’s Summation, Chapter Two, Surangama Sutra, on Medium.com: https://medium.com/tranquillitys-secret/surangama-sutra-ce0017f10d2b?source=friends_link&sk=72d18baf4c053717a13c8463297c6240

Also see my article on The Danger Inherent in Modern Secular Meditation Modern secular meditation focuses on techniques taken from ancient spiritual traditions, while jettisoning their deep wisdom born of long experience working with practicing meditators over centuries. Friends link: https://medium.com/tranquillitys-secret/the-danger-inherent-in-modern-secular-meditation-2a2fe0617ffd?source=friends_link&sk=3feb7a775cd31c2e60c8afff38031f64

Good householder,

there had been serial Buddhas before our Gotama Buddha. In a world/cosmos-period there might appear a Samma-Sambuddha who is capable to point out the way out of suffering, Samsara. When there is no full self-awakened Buddha and the Dhamma (his teaching) is unknown, there may appear so called Paccekabuddhas (Privat-Buddhas), who, althought having found the way out by themselves, are not capable to teach the path in sufficient way for others. While a Samma-SamBuddha apears or his Dhamma through direct originated disciples (Sangha of recluses) is still alive in the world awakened people (Arahats) would just arise within his Sangha, join his fellowship, hold refuge into the heritage.

There might be such as the first stages of awakening without having come direct contact with the Tripple Gems, but such happens just for those who might have gained certain access in previous existances and in every case such "reborn minor awakened" would join the Sangha.

Paccekabuddhas would not appear as long as a Sublime Buddhas teaching is still alive.

Collection of text which provide ideas about "our" Sublime Buddhas life might be found here.

[Note that this isn't given for stacks, exchange or what ever world-binding trade but for an escape from this wheel.]