Who funded the construction of buildings in history?

We know in today construction are funded by firms and governments. However, I like to know during history period like ancient times or medieval times, who fund these construction projects like in cities or towns or even in tribal areas.

Is it usually the government that fund these construction or is there more than that in history?

You can use Ancient Rome, China in BC or Gallic Tribes in 100BC. I wanted a variety of answers for different periods and cultures.