I really don't know the origin of people first making casserole dishes for meals. However, I imagine that casseroles appeared shortly after ovens and the ability to bake items. It doesn't matter who invented them or when they first became popular. The thing to know about casseroles is that they are still popular.
The term "Casserole" has a duel meaning. It refers to a particular type of food/recipe that is baked. An example would be "Baked Mac & Cheese", "Ham & Potatoes" or "Shepherd's Pie."
But the term refers to the type of dish you're using too. We will look at that tomorrow.
If you have ever been to a "Pot Luck" dinner, then you have seen casseroles at their best. This type of dinner event gives you entrée and side dish casseroles of a wide variety. If you have gone to a couple of these dinners, you have probably seen some casserole dishes that you have never even thought of trying.
They are really just another form of comfort food. They are usually made from less expensive food items but can get costly. Casseroles are normally easy to throw together, but not always. I would say they can feed a few people and the person can take a large portion or just a little. Another nice aspect of casseroles is their ability to be great as leftovers. Many of the casserole recipes will freeze well too.
Remember that many casserole recipes can be made the day before and refrigerated until time to bake. I would pull them about 30 minutes before you need to put them in the oven. It helps them to bake more evenly (inside and out). Find some good casserole recipes and take advantage of them. One of my favorites is in the blog on Friday.