The creation of Damascus steel blades in the middle east was a phenomenon that begun to take place somewhere between the 300s BC and and the crusades when these blades began to become the legend that they are today. They are known to be durable, shatter resistant blades which can hold a fine edge under very adverse conditions.
However, in the mid 1700s, the art was lost to metalsmiths, likely because of the fact that the secret of creating such blades was carefully guarded by the craftsmen who made them. There is much speculation about the chemical processes used in the creation of such blades, but while modern science can create very near matches, there is still some question about how such precise metallurgy could happen so early in history.
It seems likely that a lifetime of study likely went into the creation of the first Damascus steel blades.
Some interesting facts about this form of steel:
1: Damascus steel contains about 1.5% carbon.
2: The famous ‘damask’ pattern found on these high quality blades appeared because there are layers of cementite particles contrasting against the surrounding steel.
Here is an example of that pattern:
Image is freely available through the wiki article on Damascus steel.
Damascus steel represents a sort of peek to the metal mastery race that took place in Europe, northern Africa and western Asia from the first bronze swords on into the best steel available. The advantage of better armor and weapons became more clear as history formed, and until the age of gunpowder, Damascus steel and some similar arts found in Japan represent the height of that era. To this day, it would be hard to find a better kind of sword than a handmade Damascus blade or Japanese Katana.