What are some good early Gothic novels?

Question:

I recently bought The Italian by Ann Radcliffe and The Castle of Otranto. What are some other good Gothic novels from this time?

Additional Details

6 days ago
*The Castle of Otranto by Horace Walpole -- I forgot to mention the author.

6 days ago
Early as in, pre-Romantic (late 18th century)

Best Answer - Chosen by Asker: 6 days ago
*The Castle of Otranto by Horace Walpole -- I forgot to mention the author.