Ivanhoe question (spoilers)

I just watched the 1982 movie version of Ivanhoe. Why, at the end, does Richard I banish the Templars from England? What did they do to him? They appear to have been within their legal rights when prosecuting Rebecca, and if there’s anything in the film about any crimes they may have committed, I missed it.

I haven’t read the book since I was a kid so I don’t know if the question is answered therein, or even if Richard does banish the Templars in the book.

The brothers Malvoisin (Alfred de Malvoisin is the Templar Grand Master) conspired with Prince John to overthrow King Richard.

Is this in reality, in the book, or both?

In the book, at least:

I love the novel. My favorite movie is the 1952 Robert Taylor.