For African Americans, the one-drop rule was a significant factor in ethnic solidarity. African Americans generally shared a common cause in society regardless of their multiracial admixture, or social/economic stratification. Additionally, African Americans found it, near, impossible to learn about their Indigenous American heritage as many family elders withheld pertinent genealogical information. Tracing the genealogy of African Americans can be a very difficult process, especially for descendants of Indigenous Americans, because African Americans who were slaves were forbidden to learn to read and write, and a majority of Indigenous Americans neither spoke English, nor read or wrote it.