Before leaving Madrid to begin the perilous undertaking, the Minister of the Interior gave Boyton maps of the river and all the information concerning it he possessed, which was surprisingly little: The maps were glaringly incorrect, as was afterward learned.

Many towns that the maps located on the river were not near it.
When all was ready Paul's agent and baggage were sent to Lisbon to await the termination of the voyage.

Paul returned to Toledo to make final preparations for the trip, which was one never before attempted.

In fact, as far as was known, the river had never been navigated from source to mouth.

It is three thousand five hundred feet above sea level at Toledo, which accounts for its rapid descent.