The inclusion of the cathedral in Frostbite made for a pretty big map, with it taking roughly half of the map's size, quite possibly the biggest in the mod if it ever was released in that state. Apart from the layout, the level's graphics appeared to look much harsher and inhospitable than the Frostbite we know. A mountain was meant to cover the background in the outdoor areas but it was changed, likely due to lighting issues.
After the completion of Forgotten, Jahhur started to work on Snowstuff, sometime between late 2007 and early 2008. Initially the map was meant to take place in an island covered in snow, similar to Glacier, but later it was decided to build a castle in it. The map was originally meant to be designed for Booty in mind, with only two teams in it, something unheard of in official maps, but with the development of Holy Grail Jahhur decided to make use of that game mode instead. Due to the enormous size of the level, the entirety of the cathedral was moved to a new file and turned into its own map, later adopting the Last Team Standing game mode. Both maps were eventually released in July 2008, introducing two new game modes to Pirates, Vikings and Knights II.
The map received several name changes throughout development: it started out with the codename Snowstuff, followed by Xlumikamaa, which is finnish for Snowstuff, and finally, later in development, it was changed to Frostbite.
The following message is taken from a dev blog post was written by Jahhur on December 19th 2008, nearly six months after the release of Forstbite and Cathedral.
There haven't been any frontpage updates nor dev journal entries lately so I decided to write something to show that at least one of us is not playing Left 4 Dead 24/7. I went through my map folder and found some old versions of Frostbite and thought it would be fun to show them to the community (and some new stuff of course).
When I first started making Frostbite I had absolutely no idea what it was going to be like gameplay-wise. The last map I made, Forgotten, had a desert environment so this time I decided to go with the opposite. Now Forgotten should have taught me that planning a map and drawing a layout is always a good idea, but unfortunately I'm an idiot and just started to put stuff together in the editor (just like in Forgotten...) and came up with something like this: (see upperleft screenshot)
Took couple building parts from the first version and started to build a castle and a mountain around them. The map was going to be booty mode, this being the path between pirates and knights. Next I started with knight's base. Cathedral was originally a part of Frostbite. Unfortunately at this point I felt that the map was going to be way too much like Forgotten. And if this cathedral was supposed to be knight's base, enemies with chests would have no chance to escape from archers. I wanted to try something new and decided to turn the map to Holy Grail mode. This would give me more freedom because there wouldn't have to be balanced bases and routes for each team. This was the first Holy Grail version of Frostbite. It was big. Way too big to be exact. Being a heavy knight in this version was far from fun. I wanted to fix it without having to redo lots of areas so first I cut out the cathedral and turned it into separate map. Then removed the area on the bottom of the image and replaced it with the broken corridor part from the top.