How to do medieval calligraphy?
Art stores carry pens with nibs and ink in different colors, and if you REALLY want to be historically accurate you can grind your own pigments (no lie!). There’s people in the SCA (society for creative anachronism, like living history groups) who do this as an art form from scratch, holding their pigments in seashells and working with their own cut goose quill feathers, but you don’t have to get that detailed. Half Price Books may have some books on calligraphy in their arts section, or you can do searches online for some of the Medieval tutorials. There’s also plenty of Medieval illuminated manuscripts available to see online as well, in full color, usually at university sites. You can find those via google with some simple searches.