They were disbanded by Pope Clement V in 1312 under pressure from Philip IV who happened to be deeply indebted to the Order. However, I assume you're not asking about that. Basically, the abrupt disappearance of a major part of the European infrastructure (20,000 members at its peak, and it was 10% knights) gave rise to all the legends and speculation and legends, which have kept the Templar name alive into the modern day, hence their appearance in Assassin's Creed etc. However the order has influenced other, later, secret orders such as the Freemasons who used some Templar symbolism and many organisations claimed descent from the Templars to increase their mystery and general image.