When night's black Mantle could most darkness prove,
And sleepe (deaths Image) did my senses hyre,
From Knowledge of my selfe, then thoughts did move
Swifter than those, most switnesse neede require?
Mantle (From “Mantellum” – Latin for Cloak) is a type of loose garment serving the same purpose as an overcoat. 
 Technically, the term describes a long, loose cape-like cloak worn from the 12th to the 16th century by both sexes, although by the 19th century, it was used to describe any loose-fitting, shaped outer garment similar to a cape.
When nights black mantle could most darkness prove