Rosetta Stone: an unexpected key to a solution

Sometimes the term solution and key are almost interchangeable. This was definetly the case when the Rosetta Stone was found in 1799. For decades scientists had been searching for a specific solution to their problem: How to understand the mysterious hyroglyphs of the ancient Egyptian culture? The solution, or rather the key to understanding, came in the form of a ancient stele. In this ancient stele, three languages were inscribed in the same sentences. These three languages were: Greek, the Demotic script & the Egyptian language. Since we could already understand the Greek language, it was only a matter of time before the other languages were decrypted.
The Rosetta Stone is therefor to be understood as a key, which ultimately led to a solution. Since it still took time and effort to really decrypt the languages (how would you even know that all the sentences are the same, for example?) the Rosetta Stone is rather good example of  a key for opening up a solution, rather than being the solution itself.

http://en.wikipedia.org/wiki/Rosetta_Stone