Miletus, an ancient city in Greek designed by Hippodamus . It could be the first scheme of capital city in the world. During that time, the main purpose was trading. In Roman period, improve the convenience of living and military defense was the purpose of the capital city. You can find out this feature in some ancient roman capital city such as Rome. Rome surrounded by wall and gate. In the past, it was for the city protection. And in terms of improve living standard, Roman built different types of building for citizens. Forum, Bath, temple and so on was built by roman. So citizens were able to use those facilities and set up their business in there, therefore, more people from other places moved to there for living. Grid plan road located in Roman city as well. Every road had same length and width; it made the travel time become shorter. As Rome is a capital city, majority of government agencies also located in Rome, also it had better city plan compared to other non-capital cites.
In medieval period, many merchants and craftsmen started to set up the trading market in the city and the trading market expanded rapidly. More people worked in the city and the city became a trading center. So the purpose of the city changed from military defense to business district. Florence, Italy can be an example for this. Florence is the capital city of the Italian region- Tuscany .