More on Write Like an Angel from Infoplease:

• Write Like an Angel - Write Like an Angel (To). (See under Angel.) Source: Dictionary of Phrase and Fable, E. Cobham ...
• Angel - Angel Half a sovereign in gold; so called because, at one time, it bore the figure of the archangel ...
• Dictionary of Phrase and Fable: W - Definitions, origins, and illustrative excerpts for words, phases, and literary allusions starting with "W"