Context: In 1867, Prince Alfred, Duke of Edinburgh and second son of Queen Victoria, visited the islands. The main settlement, Edinburgh of the Seven Seas, was named in honour of his visit. Lewis Carroll's youngest brother, the Reverend Edwin Heron Dodgson, served as an Anglican missionary and schoolteacher in Tristan da Cunha in the 1880s.

Question: in what year did Prince Alfred visit the island?
Answer: 1867

Question: what was the main settlement named?
Answer: Edinburgh of the Seven Seas

Question: who is Lewis Carroll's youngest brother?
Answer: Reverend Edwin Heron Dodgson

Question: When did the third son of Queen Victoria visit the islands?
Answer: Unanswerable

Question: When did Queen Victoria visit the islands?
Answer: Unanswerable

Question: When did Edwin Heron visit the islands?
Answer: Unanswerable

Question: When did Lewis Carroll Dodgson visit the islands?
Answer: Unanswerable

Question: When did Tristan da Cunha visit the islands?
Answer: Unanswerable