In 1839, Henri Galeotti was the first European to explore the volcano, but did not hike to the summit. During the American occupation of Mexico in 1848, two American soldiers, F. Maynard and William F. Raynolds, were the first known hikers to reach the summit of Pico de Orizaba. In 1851, the French explorer Alejandro Doignon also reached the summit ad found the flagpole left behind by the Americans in 1848. During the mid-19th century Citlaltépetl was explored by many scientists, including the German botanist Hugo Fink, who was the first to record the numerous species of flora found on the volcano. In 1873, Martin Tritschler raised the Mexican flag at the summit.