A recent article on the dailymail.com website reported on a discovery made in Heslington, York. In 2009 a human skull was found there with an intact brain, and since then the brain has been examined and carbon dated by experts.
It turns out that it is one of the oldest human brains ever to be discovered and has probably preserved for more than 2,600 years, archaeologists claim.
Tests have revealed that the brain has survived because the head was buried in a sealed clay pit devoid of oxygen, soon after its owner's death.
The mystery is how this brain was preserved, when bodies buried in the ground typically rot because of a mixture of water, oxygen, as well as a temperature that allows bacteria to thrive.
When one or more of these factors is missing, preservation can occur. In the case of the Heslington Brain, the outside of the head rotted as normal, but the inside was preserved.
Experts believe the head was cut from the man's body almost immediately after he was killed and buried in a pit dug in wet clay-rich ground. This environment provided sealed, oxygen-free burial conditions.
(Source: dailymail.co.uk)