During the early 20th century, a substantial number of Arabs (mostly Christians) began arriving from the crumbling Ottoman Empire. The largest group were the Lebanese and an estimated 400,000 Mexicans have some Lebanese ancestry. Smaller ethnic groups in Mexico include South and East Asians, present since the colonial era. During the colonial era, Asians were termed ''Chino'' (regardless of ethnicity), and arrived as merchants, artisans and slaves. A study by Juan Esteban Rodríguez, a graduate student at the National Laboratory of Genomics for Biodiversity, indicated that up to one third of people sampled from Guerrero state had significantly more Asian ancestry than most Mexicans, primarily Filipino or Indonesian. Modern Asian immigration began in the late 19th century, and at one point in the early 20th century, the Chinese were the second largest immigrant group.