How old was the world thought to be when Darwin began his voyage?

When Charles Darwin began his voyage on the HMS Beagle in 1831, the prevailing scientific consensus estimated the Earth's age to be around 5,000 to 6,000 years, based largely on biblical genealogies. However, some scientists and geologists were beginning to suggest that the Earth was much older, potentially millions of years, based on geological evidence. This debate about the age of the Earth was crucial in shaping Darwin's thinking on evolution and natural selection.