What made the minoans wealthy

The Minoan civilization developed Mediterranean Polyculture, that is the practice of growing more than one crop at the time, which resulted in a healthier diet for the population, and a population growth. Additionally, it preserved the fertility of the soil, unlike when only one crop is growing.  This was not yet at standard- the Minoan civilization developed between 2000 and 1000 BC.

With a healthy population, the Minoans could also engage in trade with other places, such as with mainland Greece, which especially valued its pottery.