The Knights Templar were a medieval chivalric organization within the Roman Catholic Church.
When did they dissolve, and what ultimately led to the dissolution of the Templars?
Officially the Knights were disbanded in the early 14th century, beginning in France with King Philip IV prosecuting them for multiple reasons (the Templars had lost standing after the Third Crusade, public mistrust, and the King owed money to the order), with other countries to follow. Pope Clement V disbanded the Order in 1312.
One of the books piled up at some of the bookstore chains is titled 'The Knights Templar'. A point made in the book is that between the formation of the Knights and their dissolution there was a cultural shift in Europe toward a more secular outlook. The collapse of the western Roman empire was both natural and human disaster, natural in that there appeared to be a global cooling event that led to a lot of starvation, and human (perhaps partly cause by the natural disaster) in the collapse of what might be described as the 'advanced' civilization of Rome. This was succeeded by the arrival of the Muslims in the Holy Lands and North Africa, and the spread of Christianity throughout Europe. By the 1300s much of Europe had gotten tired of the Crusades and the Church was acting as a temporal power, in effect another power center among the kings and emperors of Europe. The natural disaster had abated, so the 1200s in particular (the High Middle Ages) were quite prosperous.
The Templars were significantly influenced by their experience in the Holy Lands and in particular in their archeology on the Temple Mount. Subsequent evidence suggests they found and removed many articles that were hidden or stored in the area, and some of these presumably contained heretofore 'hidden' knowledge. It is presumed some of this was used to their advantage in Europe, which created widespread disaffection. Over time, the order was becoming progressively less subordinate to either the Pope or the rulers in the countries they operated in. This was particularly troublesome in France, considerably less so in England and in particular in Scotland.
While formally disbanded as a religious order, elements of it appear to have survived as the Freemasons. Some find this to be a controversial assertion, particularly when the role of the Freemasons is considered in the formation of the United States from the 13 Colonies. There is circumstantial evidence that various branches of the Knights either explored or migrated into North America following the dissolution in 1312.