Most of Darwin's evidence and ideas for his theory of natural selection came from his around-the-world trip on the sailing ship HMS Beagle. The expedition was arranged by the British Royal Navy. Captain Robert Fitzroy asked Professor John Henslow, a botanist with whom Darwin had become friends in Cambridge University, for a recommendation of a naturalist for the trip. Henslow recommended Darwin.
On December 27, 1831, Darwin left England for the first and last time on the ninety foot, 235 ton Beagle. During that five-year journey, from December 27, 1831 to October 2, 1836, Darwin drew and wrote about what he saw, sent many specimens back to England, and developed ideas and questions about life that existed in the past and how it changed to become the way it is now.