Loooong ago. I copied many illuminations from ancient books. This one shows three single miniatures from the gothic era I just put together. I forgot the source, but I found the miniatures and their descriptions in a reverence book.
Top: Gawain on an amorous adventure.
Middle: Guinevra places a shield around the neck of lovesick Lancelot to heal him.
Bottom: Lancelot lifts a heavy tomb slab on a graveyard.
First I drew the outlines with technical pencil on normal, white paper and painted the whole thing with acrylics. I tried to capture the old style and even blurred and stained the background, like the original. The "gold" is underlayed with a thick, high gloss lacquer and then "gilded" with wafer-thin sheets of brass. The paper I aged with coffee, dirty fingers, water, acrylics and the use of a real sponge (better structures than artificial ones).
At last I varnished the whole piece to give it a thick parchment feel and to protect the brass from tarnishing.
I hope you like it!