Tristan da Cunha:

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.

Please answer a question about this article. If the question is unanswerable, say "unanswerable". in what year did Prince Alfred visit the island?
1867