Question: What is the name of the widow of the earl who served as both Foreign Secretary and Prime Minster from 1955 to 1957?
Sentence (from "Anthony Eden"): Robert Anthony Eden, 1st Earl of Avon, (12 June 1897 – 14 January 1977) was a British Conservative politician who served three periods as Foreign Secretary and then a relatively brief term as Prime Minister of the United Kingdom from 1955 to 1957.
Relevant evidence: Yes