The basics of immersion. Immersion, in this context, is placing yourself in the position to understand the culture and times of the people you intend to write about. I wrote yesterday that the first step is to research and read all the primary and secondary source documents about the time period that you can. This is when you begin to build your data on the historical period you are studying. I start a file of the information and add to it over time. You can see some parts of these files at http://www.ldalford.com/ under the "secrets" pages for my books. This isn't all the information, but parts of it. This type of all inclusive research works well for antiquity, but for more modern history, the number of documents becomes overwhelming. You have to select them carefully. Past a certain point in the modern era (beyond Gutenberg), I'd recommend using only primary and secondary sources. When I researched the period of the civil war for a yet unpublished novel http://www.antebellumnovel.com/, I used only primary and secondary source documents (mostly letters and personal accounts). I limited my research to Southern documents from mostly the area of the events of the novel. I used pictures and my experience of the area along with period documents and reconstructions. Because the information is so copious from that time, I had to intentionally limit my studies to the area and people at hand. This is an important point about your frame of reference. My frame of reference was the people in a certain town, in a certain place, in a certain time. The better your can bound the scope of your subjects, the better you can immerse yourself in their lives and the better you can write about them.
Let's look deeper at some very important ways of understanding a culture. Start with a blank slate. I implied this yesterday. Don't start with any preconceived ideas about the culture or the history of the times. That might blow your theme out of the water, but it is better to get the history right than to work toward an agenda that will not stand up to scrutiny. Some of the most egregious mistakes I see in historical novels set in antiquity are the obvious historical errors in them. Some of the worse are a lack of understanding of: furniture, clothing, money, cultural ideas, food, meat, sexuality, general culture, slavery, commerce, religion. These basics drive a society and culture. A lack of understanding of them will cripple any historical novel because they define the culture and time and the way people think. For example, in the West, money was not invented until ca. 600 BC by the Lydians. It was not ubiquitous in the known world until the Roman empire and even then it was rare in many areas. If you write a novel in these periods, you have to understand there is no money in general circulation until about 250 BC. You have to figure out, from history, how people traded and did business without money. Even after money is available, it is rare, and people still use the older methods of trading without it. Money, or lack of it, drives the entire culture and ideas of the people. A book with money in it in the periods mentioned (definitely prior to 600 BC but in varying degrees until much later) is just silly. Ubiquitous furniture is another example of a lack of understanding about the past. People did not have furniture, except the very wealthy and royalty, until very late in human history. People in antiquity in the West, especially the wealthy, lay on their sides to eat and sat on the floor or cushions. Slaves sat up to eat. There were few chairs. Tables were nonexistent or very low and small. There were few pots or pans or plates and no utensils used for eating. I'll get into more details about these subjects tomorrow, but you can see how important these details are for understanding about the past and history.