Songs have been sung since time immemorial. It is also quite common for bards participate in filk singing. This is when a bard uses elements of an already well known song and adapt it to fit a particular theme.
I used You Tube to understand the tune of the Ylvis song What Does the Fox Say. Then I looked up the lyrics and printed them out. I went through the lyrics line by line determining how many syllable each line used. Then I brainstormed the with other SCA members during a virtual social chat time on what the different peerages were. We delved even deeper to learn intrinsic elements of each peerage. Then I played around with word choice/order to make it fit within the parameters of the song. In order to include the 4 main peerages, I had to take out a chorus section of the song and replace with a verse section.
I confess I do not know of any medieval filk songs so I can not say what I have done differently, I suspect the process is relatively the same.
I can honestly say I enjoyed working on this song and the result of the finished product. I do think it would be better sung with more than one person, like the music video of the original song but other than that, I don't think I would do anything different.
Ylvis song What Does the Fox Say?
Filk Music- Wikipedia