Interesting topic Vandoo! and as always it is fascinating to look into all aspects of arms and armor, from what they developed into in modern times into the deeply intriguing weapons of old.
As Mark has noted mentioning the massive guns of Malta, it brings to mind the fabled gun at Edinburgh, Mons Meg.
This huge bombard was apparantly built to order for the 'Grand Duke of the West' Philip (the Good) of Burgundy, and first fired in 1449 at Mons (in Wallonia). The 'good' duke is better known for his capture of Joan of Arc at Compiegne.
This huge medieval supergun was about 15 feet long, weighed 15,366 lbs and fired a ball of around 400 lbs! It is noted that the gun could only be fired about 8 times a day from the intense heat generated by the massive powder charge.
The gun was presented to King James II of Scotland by Philip about 1457, and apparantly suffered a burst barrel when it was fired about 1680, with suggestions of possible sabotage.
I always wondered what in the world 'Mons Meg' meant, though clearly the Mons referred to the city in Flanders where it was from. According to what I could find in OED, the term 'meg' referred loosely to any huge ordnance, and or to the loud noise or report. In one reference around 1700, it was used describing loud noise of ringing bells and the discharge of 'roaring megs'.
Another large gun which is lesser known but appears of the same ilk as Mons Meg, was the 'Great Cannon of Ghent', and of similar construction of welded iron bars. It was known as Dulle Griet (=foolish or evil meg) and often termed the red devil as it was painted red. It also bears insignia of the Order of the Golden Fleece (created by good Philip in 1430) and the cross of Burgundy.
Right now in the travels of the 'bookmobile' (our trusty RV) we are situated at a lake in Killeen, Texas, quite near Ft. Hood. At often odd hours it seems we are somewhat near enough to hear the loud booming reports of the 'megs'
being fired on the artillery range. At times they are loud enough to rattle windows and you can almost feel the concussion! I often wonder if the firing at 3AM is to intensify the sound, which permeates the otherwise still night.
The attached are Mons Meg, Philip the Good, map of the area of origin of Mons Meg (Mons is called Bergen , the Dutch name, on the map), and Mons Meg as it appeared c. 1680.
All best regards,
Jim