Were the Knights Templar heretics? Dr. Rainy (I)

The Knights Templar were not heretics by Roman Catholic standards. By the standards of the United Free Church of Scotland they... left something to be desired, but I'd probably let one into the Bible Class at Glenshilloch. They were actually devout Catholics. In the Middle Ages many groups were accused of heresy, ranging from the dualistic Cathari to the evangelical (and evangelistic) Waldenses. In fact, one of the easiest ways to get accused of heresy in the Middle Ages was to be extremely devout! This is true in some circles today.
Accusations of heresy were brought against the Knights Hospitaller in 1238. Pope Gregory IX declared that they had heretics in their midst. What the Hospitallers did about this is... not much. In 1312 the Beguines and Beguins, lay groups of women and men who lived together without taking formal vows, were accused of heresy. Pope John XXII condemned the Spiritual Franciscans for dividing from the Franciscan order and trying to maintain St. Francis' original rule! And the Teutonic Knights of Livonia were actually excommunicated for heresy in the late thirteenth-early fourteenth century. The Teutonic Knights got the charges dropped.

Accusations of heresy did not mean that the 'heretic' was anything of the sort.