Dim Sum History
If you search for dim sum history on the web you will find many sites giving you all sorts of information and many of them contradicting each other. Even for the simple meaning of the two Chinese word dim sum there are many interpretations. It is like interpreting some verses of the bible there are definitely multiple meanings of the two word dim sum.
The word dim literally means point. The word sum literally means heart. Put the two words together means point to the heart. Now that really have no literal meaning. What is point to the heart means? So people becomes very creative and start putting many meanings to dim sum. The real meaning of dim sum is just small snack or small dishes of food. So in theory you can have dim sum in any kind of ethnic food. And in Chinese food you can definitely have dim sum in different cuisines of Chinese food. Usually if you just say dim sum you refer to the Cantonese style cuisines of food. For other cuisines you will add something on top of dim sum like Shanghai dim sum.
Where does the tradition of dim sum or small dishes of food come from? I am going to speculate a little bit using my background knowledge. I use to ask myself why do we have thousands of different dishes of Chinese food? You can literally eat a different dish of Chinese food a day and do not have to repeat the same dish for many many years. I blame it on the 6 thousand years of Chinese culture under the system of "kingship". What do you think a king of China or the king of "middle kingdom" do all day? The history book will tell you many of them have done great things or achieve many goals. The real truth is the king only tell others to do all those great things, he himself just eat and play all day. The king has hundreds of chefs. Each day they prepare hundreds of dishes of food for the king and he tasted just a few of them. This bad habit is spread all over the palace where hundreds or thousands family members of the king lived. Obvious they cannot all have hundreds of full dishes of food each day for them to just sample. So very small dishes of food but extremely well prepared are offered to the king's family. There is one restaurant in Beijing (inside North Sea Garden) that prepares and offers "palace food". Small dishes of extremely well prepared food are from the king's palace and then spread to the city and becomes dim sum. (Do not email me if you have a Ph. D. degree in Chinese History and you want to disagree with me. Feel free if you have a Ph D. degree in enjoying good food or comedy) For those who wants a real Chinese history point of view here is a web site you can visit.
How did dim sum get to Canton? There are some popular saying in Chinese where are the best places to do or get different things. Canton is consider to be the best place in China when it come to eating food. When it comes to food the tropical or warmer climate areas has an advantage over colder areas. You can grow more varieties of things and you have more harvests of crops in warmer weather area. In the colder area you need to preserve food more often and thus you have less fresh supply of material. You will find more spicy food in the north. In Canton you have a lot of fresh food supplies and thus more choices of how you can cook them.