New writers are often tempted to explain everything at the beginning of a book. It seems to make sense. The reader will want to know where the protagonist comes from, what makes him tick, and so on. So why not just tell him, up front?
The problem is that the reader doesn't care yet about your protagonist. Nothing has grabbed the reader's emotions. It's like when you first meet someone. If this person sat you down and started naming off her grandparents, uncles, and aunts, you'd politely excuse yourself.
So you need an attention-grabbing situation that engages the heart of the reader, as discussed in a previous blog post.
But you need more. You need enough detail so that the reader doesn't feel disoriented. The reader needs to be aware of the time period, the geographical location, perhaps how two characters are related to each other, and other minimal set-up details as soon as possible. Without them, the opening may come off as unreal and dreamlike, not attention-grabbing.
In the case of a historical novel, often the writer will put a header on the chapter informing the reader of the year, the location, and sometimes the point-of-view character in that chapter. That's one way to do it.
But there are ways to let these things be known without actually telling the reader. Look at the first pages of some recent published books and study them. Can you see how the writer drops hints about these set-up details?
St. Simons. They're in the Caribbean somewhere on a vacation. And we've got a bit of background on the man now.
Pull out some other recent novels and see what you find!