Phineas Gage WAS an ordinary man. That is, until he was struck with an iron rod, called a tamping iron, while constructing a railroad. The iron rod went through his cheek, behind his eye, came back out of his head, and landed thirty feet away. He then, miraculously, sat up and started talking. The men he worked with starting calling for a doctor.
They took Phineas to where he was living. Fortunately, there was a doctor nearby. The doctor came over and bandaged Phineas' head. The doctor discovered that the tamping iron had gone through a part of Phineas' brain called the frontal lobe. The frontal lobe controls your emotions, behavior, and personality.
Since the tamping iron went through the frontal lobe, Phineas was no longer the same. He said some things that didn't make since, he would act like a child sometimes, and his emotions were all over the place. Phineas lived in the 1850s, therefore, nobody knew about bacteria or infections, so when Phineas' brain got infected, unfortunately, nobody could save him. The bright side, is that we learned a lot about brain science because of Phineas. Maybe sometime in the future, we will fully be able to understand how the brain functions.