Solar technologies generate a majority of the power used during space missions, keeping life support and other vital spacecraft systems working. Solar power is so critical that NASA spends considerable time and money to make solar panels must more efficient, lightweight and affordable.
Well one reason why they struggled was because the priest had higher authority than the king himself did but I don't really know why or how it lead to the crusades in the holy land. I'm sorry I couldn't help you fully but I tried.
