If you're looking for a great place to start in your online research, this is it. This site is maintained by Paul Halsall of Fordham University. This mega site, with its thousands of pages, is sure to please any history buff, or anyone simply looking for information. The site is divided into three main sections, the Ancient History Sourcebooks, Medieval History Sourcebooks, and Modern History Sourcebooks. Also included, but not limited to: East Asian History, Global History, Islamic History, Jewish History and Women's History Sourcebooks.
This is another great site if you're looking for research; it is one of my favorites. Each week, this site is updated with original articles from Guides in each area of history. These guides are knowledgeable in their fields of study. You can find out more about the guides' credentials by clicking on their pictures at the top of each topic site. The topic sites include: 20th Century History, African History, African-American History, American History, Ancient/Classical History, British History, European History, Medieval History, Military History, and Women's History. Also included at each of these sites are forums where you can post your question(s) that will be answered by forum members knowledgeable in answering your questions. Also, you can get into contact with the guides directly by clicking on their pictures and you will see their "bio pages". Here you will see the emails where you can contact them.
This site has loads of information on history; and from what I can tell, it appears to have history-related information on every country in the world! This a great place to start if you're looking on information on a particular country, province or state.
"Making of America (MOA) is a digital library of primary sources in American social history from the antebellum period through reconstruction. The collection is particularly strong in the subject areas of education, psychology, American history, sociology, religion, and science and technology. The collection currently contains approximately 8,500 books and 50,000 journal articles with 19th century imprints. The project represents a major collaborative endeavor in preservation and electronic access to historical texts."
Although this site doesn't have any specific information related to the historical fiction genre, there is a lot of information to help the historical novelist get his/her work published.