early, late

Do not hyphenate compound modifiers with these words unless ambiguous or hyphenated by M-W:

            early morning dew

            late afternoon sun

            early 16th-century painting

    mid to late 19th-century home

Lowercase before major geologic times and cultural periods:

            early Pleistocene

            late Renaissance

but     Early, Late Bronze Age

            Early, Late Classic (Maya)

See also period.