Railroad worker who survived a metre-long iron rod passing through his frontal lobe in 1848. His personality changed forever — the canonical case in neuroscience.
From Wikipedia
Phineas P. Gage (1823–1860) was an American railroad construction foreman remembered for his improbable[B1] survival of an accident in which a large iron rod was driven completely through his head, destroying much of his brain's left frontal lobe, and for that injury's reported effects on his personality and behavior over the remaining 12 years of his life—effects sufficiently profound that friends saw him as "no longer Gage".