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late, early

Do not hyphenate compound modifiers with these words unless ambiguous or hyphenated by Webster's:
            
late afternoon sun
            early morning dew
            late 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)