Just a quick thought ...

I was thinking about the pros and cons of a Book of Centuries vs a timeline.

A Book of Centuries is more portable, and easier to just flip through a make a quick note of something interesting, or a little sketch. It's also very easy for each child to have his/her own book, since they are easily stored. The downside is that it can be hard for children to visualize all of history and the flow of events, when stopping to turn pages, and each page seeming like a separate piece.

A timeline is very visual and allows a child to see at one glance the entire sweep of history. It's not very portable though, and to be convenient to see and out of the way of little hands pulling it down, it needs to be UP ... like near the ceiling. This makes it difficult to add a quick note or sketch. Also, something so big would probably be shared among all the children in the family, which while fun might not give them as much a sense of ownership of history.

A solution hit me like a ton of bricks.

An accordian-fold timeline, with holes punched to fit inside a binder. Inside the binder the pages would turn for quick note-taking and personal perusal. Remove it, unfold, and hang on the wall for a shared history lesson display.