The Knights Templar is a well-known order. They hold up a firm spot in the history of religions. What are less known, however, are the Cistercians, kin of the Templars. While the knights are known as the warriors, the Cistercians were the monks with the white mantles.
In 1098 just, a year prior to the Crusaders' storm over Jerusalem, a monk of the Benedictine gathered a group of followers and took off to the Citeaux, where he started a new abbey, known later as the Cistercians.
The monk, Robert, left the order as he was discontented with the members not following the St. Benedict rule, the same rule that the Templars were based upon. The monk believed that if he started a new group in the wilderness, he could begin a new thing. However, the Benedictines back at Molesome were dissatisfied with him going away, which is why they convinced the Pope to force him to go back to his first order. At Citeaux, the monk was replaced by Alberic.
Although Alberic was not the first founding member of the order, it is said that he is the one who is responsible for the white mantles. However, it is very likely that Stephen Harding, his next-in-line, was the one responsible.
Later, the white mantles became what distinguishes the Cistercians and the Templars from all other monastic groups. The monkhood started growing as more members joined the order, seeking belonging and ready for devotion.
As the Templars grow in numbers and wealth, the Cistercians did too. Both orders were tithes and taxes free, and the members were experts of trading, farming, and even industry.
The connection between the two institutions was not random. The same rules that founded the Templars held the white mantled monks in recognition and admiration. For instance, when a knight was forced to exile the order, he was to join the Cistercians as some sort of rehabilitation, as he was not allowed to go back to secular life.