I think that before you can ask that question you need to define precisely what you mean by "enlightened".

Enlightened about what? Enlightened in what way?

I've been looking at potentially buying a college video course on this very topic. It's 36 lectures long and it covers the four most influential "Enlightened" men in history. They are, Buddha, Confucius, Jesus, and Mohammad. Although I'm not sure why they didn't also include Lao Tzu and his philosophy of Taoism.

Of course many other individual could be said to have been "Enlightened", they just didn't become spiritual teachers, or they just didn't have a very profound affect on large cultures.

Things these men all appear to have in common is that they all recognized and taught the 12 laws of Karma.

However, they seem to have all been drawing different conclusions about what happens to us after we die. And those conclusions were always in-line with the spiritual folklore, beliefs, and/or philosophies of the cultures in which they lived.

For example Buddha lived and taught in a culture where reincarnation was viewed as the essence of life. So he framed his wisdom around that "belief".

Jesus lived and taught in a culture where a judgmental godhead determines the fate of souls depending on whether they are naughty or nice. So he framed his wisdom around that "belief".

Evidently becoming "enlightened" doesn't provide anyone with any supernatural knowledge that they didn't already possess before they became "enlightened".

I've studied the concept of enlightenment since about the early 70's. I've often wondered if it is possible to somehow become suddenly aware of the true nature of reality and the true fate of the human condition. After having recognized that all the men who were deemed to have been 'enlightened' all had different views on the ultimate essence of reality and fate of the human condition, it's pretty safe to say that "enlightenment" cannot be the spiritual knowledge that many profess it to be.

I think the Eastern Philosophies that place "enlightenment" in the framework of simply recognizing that individuality is an illusion are probably the closest to getting at the essence of what "enlightenment" truly is.

In fact, in that sense an atheist could become 'enlightened' and still be an atheist. In fact, I personally believe that many atheists are indeed enlightened people.

Deepak Chopra teaches the concept of enlightenment. I think its safe to say that he would personally consider himself to be an 'enlightened' person. After all, what sense would it make to teach of something you are not personally aware of?

In an interview he was once asked how a person can know if they are "enlightened", and Deepak proceeded to give a list of things that such a person would know to be true. After having gone through his list I have no choice but to conclude that I am indeed an "enlightened" person based on his criteria.

I think a lot of people are "enlightened". One of the things that was not on Deepak's list was an idea that you would suddenly become aware of the true nature of reality or the precise fate of the human condition, or that you would suddenly know what happens after death. Those things are not required for "enlightenment". At least not by the criteria he gave.

So again, it comes down to what you mean by "enlightenment"

Buddha was said to be enlightened, but he believed in reincarnation and that the main goal of a human should be to get out of the cycle.

If we can trust the biblical account of Jesus to correctly express his beliefs, then Jesus held an entirely different notion of what life was all about and the fate of the human condition.

So could both of these men have been 'enlightened' if they both held different views of reality?

I guess it all depends on what we mean by "Enlightened" Enlightened about what?

I think before a person heads out on a journey to become "enlightened" they should define what they mean by that. Only in this way can they ever know whether they have ever achieved "enlightenment".

For example, if to be "enlightened" means that a person recognizes the transient illusion of individuality and basically understands the 12 laws of karma on an intuitive level. Then I would say that I'm an "enlightened" person.

On the other hand, if to be "enlightened" means that a person has gained some supreme knowledge of precisely what happens after death, etc. Then no, I'm definitely not "enlightened", and I don't expect to ever become "enlightened" whilst in the human condition.

Who were they? Who, through the centuries, have these people been? And, what did they have in common? What made them "enlightened"? What did they do differently from the rest of us that allowed them to become "enlightened"?

No one is "enlightened."

I agree with Gwendolyn. Those whom you may perceive as more enlightened than you, or even less so, are really no different from you in any way. We all have the same potential. Very few people have lived up to it to the extent that many revered figures have have, but it is still there in all of us.

"Don't try to be a great man. Just be a man, and let history make it's own decision." ~Zefram Cochrane