During their extended stay in the Holy Land they had extensive exposure to eastern religions, philosophy, knowledge, and medicine. Typically badly outnumbered in engagements, they fought with legendary bravery, and often with brilliant insight. Over the centuries, through patriarchy of the Catholic church, generous donations from wealthy families, and military conquest, they amassed wealth and power rivalling any organization of their age. The Templars implemented the earliest system of banking in the world, using "cheques", where a person could deposit money in one Templar facility and be issued a cheque which could be withdraw far away at another Templar location. They were perhaps the most powerful financial organization on earth during the middle ages, and used it to good effect.
Though initially the Templars were mostly of French origin, over time Germanic, Iberian, English, Scottish, and Eastern European membership grew (though always they were a French dominated organization- particullary with reguard to their leadership.) They had during that time an almost unheard of method for selecting a new Grandmaster (amounting to democratic election- though a sitting Grandmaster's nepotism went a long way).
From their contact with Islam, Judaism, and the accumulated knowledge then existing in the East (which was the most scientifically and medicinally advanced at that time), they adopted different styles of dress, mannerisms, philosophy, theology, and a great appreciation for the value of math and science. These last two they employed in their military endeavours in sailing, seige warfare, and construction techniques, allowing them to build some of the most advanced fortifications, and perhaps one of the largest shipping fleets of that era. Their knowledge of masonry, medicine, celestial bodies, mapping, and nautical tools was extensive, and increased the efficacy of their all of their endeavours, military, merchantile, or otherwise.
(From Knights Templar History)
It was recently pointed out to me that in Switzerland, roughly around the same period the Order of the Templars was being disbanded, a bunch of previously not-particularly-militant peasants beat the Austrians. Then went on to found a rather secretive nation that specialized in (1) mercenaries and (2) banking.
And if that's not weird enough... reverse the colors on the Swiss flag and compare it to those of the Templars.
