@SugarcoatedStacie Said
Yes, the Templar's existed. They were warrior monks sent out by the Church to take back lands and push back attacks from the Turks (Muslims) They bulit a large group of warriors, monks and had worldwide pull. And yes, they were some of the first Europeans to become interested in banking and credit worldwide.
Their fortifications are beautiful, truly masterfull.
They threatened the Pope's power, yes. They began to yeild more power then the popes had intended- so the Pope said that they were heretics and commited several acts of sin (he said that their rites included blood-rituals, devil worsip and sodomy.) With these made-up charges the church launched a full scale attack on the Templar knights and did away with them ruthlessly and quickly. [Yes, this did happen on friday the 13th as the above poster said.]
Any myths about them and the 'Holy Grail' both in ledgend and in Dan Brown's novel the DaVinci code are however untrue. These knights did not protect the holy grail.
The History Channel has done a lot of really nice programs about them- ex. Lost World's episode The Knights Templar is available on DVD + they did quite a few things in reference to the historical accuracy of Dan Brown's novels, including one show proving using DNA evidence to see if the french Marovinigan kings could have orriginated in the middle east and could have been decendents of Jesus Christ.
To correct you a little, they were not sent out by the church to take back the holy lands. Originally, they set themselves up to protect pilgrims along their way to the holy land, setting themselves up it is beleived in the ruins of the temple of solomon.