Two great mystery series:
first book- A Shrine of Murders by CL Grace (especially interesting if you have read the Canterbury Tales)
and
first book- Mistress of the Art of Death by Ariana Franklin
Unfortunately the author of that second series died before she could finish her series so its last book kind of leaves you hanging.
Also:
Maid Marian by Elsa Watson
The Kings Persons by Joanna Greenberg
Child of the Northern Spring and subsequent novels in the trilogy by Persia Woolley
And I definitely second The Name of the Rose