How did Lewis Henry Morgan begin the systematic study of kinship terminology?

Lewis Henry Morgan began the systematic study of kinship terminology around 1856, when his interest shifted to the unique ways the Seneca nation designated relatives compared to Anglo-American conventions.1

After discovering that the Ojibwa people used virtually identical kinship designations, Morgan conjectured that these systems might provide evidence of the Asiatic origins of American Indians. This hypothesis led him to conduct extensive, far-flung investigations into the kinship terms used by numerous other cultures.1

He compiled his findings in his pioneering 1871 work, Systems of Consanguinity and Affinity of the Human Family. This study inaugurated the modern anthropological analysis of kinship terminology, most notably by establishing the fundamental distinction between "classificatory" systems—which group collateral and lineal kin under the same terms—and "descriptive" systems, which maintain clear separations between them.12