Based on the provided reference, Captain Levison Wood embarked on an epic journey with the specific aim of becoming the first recorded person ever to walk the entire 4,250 miles from the source to the sea of the Nile River.
According to the information available from his journey, Captain Wood had completed almost 1,000 miles within the first three months of his expedition. His stated goal was to achieve this unprecedented feat as the first documented individual.
This indicates that, at the time the reference was made (during Captain Wood's attempt), no one before him had been officially recorded as having successfully walked the entire length of the Nile.
