A century ago, Albert Einstein formulated one of the most important scientific ideas in history.

The theory of relativity was proposed in four lectures delivered in Berlin in November and December 1915.

It was essentially a new theory of gravitation, superseding Sir Isaac Newton's, which had lasted for 250 years.

It has had a profound effect, not only on scientific thought, but also in its practical applications. Anyone who uses GPS navigation in their car, for instance, has reason to thank Einstein.

Hanoch Gutfreund, professor of theoretical physics at Hebrew University, calls it "the most sophisticated construction produced in a single human brain, a complete revolution of our ideas about space, time and gravity. The cornerstone of modern cosmology."

To mark the anniversary, Prof Gutfreund is embarking on a speaking tour of Berlin, Warsaw, Madrid, and this week, London.

Einstein's influence was felt strongly in the founding of the university in 1925. It owns the rights to his image and name, and houses an archive of more than 82,000 of his documents.

The institution is celebrating its 90th anniversary, which may not have been possible without Einstein's blueprint, an article entitled The Mission Of Our University which the museum's president, Prof Menahem Ben-Sasson, described as a "very important document".

Israel's first university was built on Einstein's idea that it should be "a place where the universality of the human spirit manifests itself", where "science and investigation recognise as their aim, the truth only".

Prof Ben-Sasson says Einstein continued to guide the institution. He said: "Whenever he felt the administration was not going in the right direction, he invested his time, effort and connections to take the university along the route he and other great scientists thought was the right way to make it one of the leading universities worldwide. Einstein said again and again to people: 'if you believe in the future of the state of Israel, if you think Jerusalem is an important place, there is no way that this will be achieved without a strong Hebrew University'.

"In this way, Einstein never left the university."

And through his role in creating the university, Einstein made a key contribution to the success of the state of Israel.

Describing it as "the start-up of the start-up nation," Prof Ben-Sasson said its status as a research centre had fuelled Israel's pre-eminence in the field of high-tech.

"How many examples have you got where a university creates a state?" he asked. "This university put a major sign on its flag to be about science. The ultimate truth - not religion, not anything else, before science.

"So when you see science affecting daily life in Israel, you realise there is a straight connection between the university and the state of Israel."

As one of the most famous physicists of all time, it is perhaps no surprise that Einstein rooted his Judaism in science.

The man who once said that "science without religion is lame, religion without science is blind" considered the two to be intertwined rather than diametrically opposed.

Prof Ben-Sasson said: "His perception of Judaism was a universal message of respect for the individual and for human rights, but what was unique about that heritage, according to him, was learning for its own sake and the pursuit of truth.

"It is for those aspects of Judaism that he said 'I am a Jew and proud of it', and he perceived our university as the arena in which these values would come into prominent play in modern times."

So, how can his theory be explained?

"Suppose you have a trampoline," said Prof Gutfreund. "And in the middle of the trampoline you put a large mass. What will that mass do? It will create a valley in the trampoline.

"Then you roll a marble on that trampoline. If it has enough velocity, it will pass by the large mass, but in a curved trajectory, or if it doesn't have enough velocity it will simply fall into the big mass.

"Suppose you are an observer and see this phenomenon, but without the trampoline. You would see one mass, one particle (the marble), and the particle move towards that mass. So you would guess that there is a force between them, attracting them.

"But there is no force; it is a geometrical property of space. This is the essence of Einstein's theory."

He added that "understanding this is a source of happiness".

It's also practical. Key to the creation of Sat-Nav technology, for example, was the understanding that "a clock on earth is slowed down in respect to a clock in a satellite. It's a very tiny effect, but it's strong enough that it has to be taken into account if you want to have an effective GPS system."