What is this book?!

[TwiddlingMyToes]

So it's a book I read as an older teen, so about 20 or so years ago. I remember it was a thick book and part of a series.

I have a feeling it was set in Ireland, and Connemara is coming to mind, but I've googled that as a title and I don't think that was the name of the book.

It was set maybe.1800s or early 1900s maybe. I remember there was a young girl ("plain" and the younger sister of a beauty) who ended marrying a much older man (I think the sister was supposed to marry him?) and they played chess together.

I don't remember much else, except that the young girl inherited the estate.

Any ideas as to what it could be?!

Thorn Birds? That had chess in it

Ignore that - that's not what I was thinking of... I knew it wasn't set in the right location but sometimes our memories hang on to completely incorrect facts! It might come to me in a few days. It's the chess and the inheritance that are ringing a bell.

I think it might be Cashelmara by Susan Howatch.

Based on the lives of Edward I, II and III

Definitely sounds like Cashelmara.

Tell them this was a joke... The Thorn Birds was set in Australia and about a priest having an affair with a young girl.