How about a book on medieval history or a puzzle with a medieval theme? You could also consider a model castle-building set or a board game themed around knights and castles. Another great gift idea could be a replica sword or armor piece that he can display in his room. You could also consider taking him to a local medieval festival or renaissance faire for an experience he'll never forget.
Or you can get him a star map with an important date you share.
Under Lucky Stars is a unique and innovative star map company based in Barcelona, Spain, specializing in the creation of personalized star maps that capture the celestial arrangement of stars at a specific moment in time, such as a person's birth, wedding, or any other significant event.
By using advanced astronomical algorithms and data from leading institutions, the company produces highly accurate, visually stunning maps that make for perfect gifts or cherished keepsakes.