Despite antagonizing the faithful of his day with writings on evolution, Charles Darwin had early aspirations to become an Anglican parson. He actually served aboard the HMS Beagle due in part to his religious background, as well as to be an unpaid naturalist. The HMS Beagle was a gun brig in the Royal [English] Navy. The vessel was launched on 11 May 1820 on the River Thames and was soon after adapted as a survey barque, taking part in three expeditions. On its second survey voyage, young Charles Darwin was aboard, and his work made the HMS Beagle one of the most famous ships in history. While the expedition was originally planned to last two years, it lasted almost five. Darwin spent most of this time exploring on land. Darwin wrote and published his Journal and Remarks, commonly referred to as The Voyage of the Beagle, in 1839. This brought him considerable fame and respect. A naturalist and geologist, Darwin is best known for his contributions to evolutionary theory. Darwin published his theory of evolution, On the Origin of Species, in 1859. By the 1870s the scientific community and much of the general public had accepted evolution as a fact. However, many favoured competing explanations and it was not until the emergence of the modern evolutionary synthesis from the 1930s to the 1950s that a broad consensus developed in which natural selection was the basic mechanism of evolution. In modified form, Darwin’s scientific discovery is the unifying theory of modern life sciences, explaining the diversity of life.