This makes it a very important little manuscript, because John has been almost unanimously held by scholars to be the latest of the four gospels.
So if copies of John were in circulation by 125, the others must have been written considerably earlier.
The earliest manuscript of the New Testament was discovered about 50 years ago.
Carbon dating and other chemical methods are rarely used in determining the age of manuscripts.
Instead, a paleographer analyzes the handwriting of the text, which yields a much more precise date than carbon dating would.
Other important manuscripts date to the fourth and fifth centuries.
The manuscripts dating from 100 to 300 AD are almost entirely papyrus fragments.
However, a large number of ancient manuscript copies have been discovered, and modern translations of the New Testament are based on these copies.