Wealth, power, expansion of territory, and a state religion that made "spiritual expansion" a life goal for monarchs.
If you read about various big colonial enterprises, eg the Spanish colonisation of the Americas it's rare to see technology mentioned as a motivation that drives the action, at best it's an enabler that provides success when expanding into less advanced territory.
eg:
The Spanish expansion has sometimes been succinctly summed up as being motivated by "gold, glory, God", that is, the search for material wealth, the enhancement of the conquerors' and the crown's position, and the expansion of Christianity to the exclusion of other religious traditions.
https://en.wikipedia.org/wiki/Spanish_colonization_of_the_Am...