GF's pseudonym was Johnson - he gave it, on arrest.
And he was a Catholic - who felt his religion was badly treated by the more powerful Protestants.
Bearing in mind that only about 10% of our current MPs are Catholic (less than 20 are Tories), he may well have had a point.
Principled, he was a soldier who fought in Spain, against the Dutch - and was by no means the main man, in the Plot.