Death at the Dolphin is a detective novel by Ngaio Marsh; it is the twenty-fourth novel to feature Roderick Alleyn, and was first published in 1967, the plot centers on a glove once owned by Hamnet Shakespeare, Hamnet  was the only son of William Shakespeare and Anne Hathaway, and the fraternal twin of who?
Hamnet Shakespeare: Hamnet Shakespeare (baptised 2 February 1585 – buried 11 August 1596) was the only son of William Shakespeare and Anne Hathaway, and the fraternal twin of Judith Shakespeare.
i don't know