Knightfall is of course a fictional TV drama about the persecution and execution (by burning at the stake!) of the Knights Templar by King Phillip IV of France. Who says nothing fun happens in the 14th century?
The Knights Templar (aka the Order of Solomon's Temple) were a militant arm of the Catholic church and heavily involved in the Holy Crusades. They also were among the wealthiest of the church orders and in fact developed many early forms of banking as used even today. Unfortunately this led to King Phillip owing them a lot of money and when the Holy Land was lost and they lost face he took advantage of the opportunity to destroy the order and have a lot of them killed. Be careful who you lend money to.
The show (filmed in the Czech Republic and Croatia) follows fictional Templar leader Landry du Lauzon and his quest to find the Holy Grail. The story is fictional for the most part but follows historical events and figures. Fans of this show will enjoy any of these t-shirts, hoodies, long sleeves, and tank tops in mens and womens with sizes up to 6XL.