How so we know that some people of African descent were not slaves in Spain's American colonies?

Some people of African descent in Spain's American colonies were not slaves because they were born into free families or obtained their freedom through various means such as manumission, military service, or purchase. Others may have escaped or been granted freedom due to exceptional skills or services provided to their masters. It is important to recognize the diversity of experiences for individuals of African descent in colonial societies rather than assuming all were enslaved.