By request I am republishing this article from The Tolkien Society below - this is an interesting little piece of the creation of the history of Middle-earth, in Tolkien's own handwriting.
Dreweatts & Bloomsbury Auctions are auctioning a letter which explains the creation of Estella Brandybuck née Bolger, the wife of Meriadoc Brandybuck, on the 22nd October 2015.
When The Return of the King was published in 1955, Tolkien created Appendix C which did not contain a wife for Meriadoc Brandybuck (Merry). In the Note on the Text by Douglas Anderson in recent published copies of The Lord of the Rings, Douglas wrote "Soon after this he sent a small number of further revisions to Ballantine for the appendices, including the now well-known addition of ‘Estella Bolger’ as wife of Meriadoc in the family trees in Appendix C."
Additional information on Estella Bolger is given in note one of The Family Trees chapter of The Peoples of Middle-earth (edited by Christopher Tolkien) "On one of his copies of the First Edition he added to the genealogy of the Tooks… ‘Estella’ as the sister of Fredegar and her birth-date 1385; and to the Brandybuck genealogy he added to Meriadoc ‘= Estella Bolger 1385’, noting beside this that he told a correspondent in 1965 that ‘I believe he married a sister of Fredegar Bolger of the Bolgers of Budgeford’."
Dreweatts & Bloomsbury Auctions are auctioning the letter mentioned in The Peoples of Middle-earth on the 22nd October 2015 in their 20th Century Books and Works on Paper sale in London.
The auction gives some additional detail on how Tolkien created the character of Estella. The letter was dictated, typed and signed by Tolkien’s secretary of the time, Baillie Knapheis, and the typed text stated "Your question about who Merry married is an interesting one, but unfortunately the answer is not recorded."
While the letter was being typed Tolkien appears to have decided that the answer should be recorded i.e. Merry should be married and that a suitable candidate would be the sister of one of Merry’s best friends, Fredegar (Fatty) Bolger.
Tolkien came up with the name, Estella and also added her to the Bolger and Brandybuck family trees in The Lord of the Rings. Estella’s name was also underlined, indicating that she had been a guest at Bilbo’s party. Due to various publication problems, Estella has only recently appeared in all copies of the Appendix C of The Return of the King.