What is that novel?

A modern novel, a story within a story. The framing story is about a poor grad student whose focus is a famous 19th century poet, and how he and a woman discover the poet’s secret life through a series of adventures. The inner story is of the poet, and quite a bit of his poetry in an authentic 19th century style is included.

I read it some ten years ago and I cannot for the life of me remember the title or author.

It made a splash when it was published.

Possession, by A. S. Byatt?

YES. Thank you. Driving me mad, it was.