 The "holy races" have been considered variously as either humanity or the gods.The notion of humanity as "Heimdallr's sons" is otherwise unattested and has also resulted in various interpretations.Some scholars have pointed to the prose introduction to the poem "Rígsþula", where Heimdallr is said to have once gone about people, slept between couples, and so doled out classes among them (see "Rígsthula" section below).