If we were going to learn about medieval art, castles are kind of required. Kindergarten was very excited to make their own castle, but I had to teach them that there's more to castles than what they see in a Disney movie.
Our focus castle was Bodiam Castle in England, shown above. It's a fairly well preserved example of typical medieval architecture, and with it's symmetrical design, it's great for teaching balance to kinders. We started with a lunch sack, added a portcullis (the door+iron gate), arrow loops, and carefully glued paper towel tubes to the sides to make towers. After a brief lesson in cutting crenels (the notches at the top), castles were complete. For the sake of creativity, each student was encouraged to add something to their castle to make it unique-princess, king, knight, giant fire-breathing dragon...you get the idea. If too much of something was chopped off during construction, we used the excuse it was destroyed in battle (and amazing tales ensued).
My mixed age class made castles, as well, but since they're a little older, we went more in depth with castle construction and vocabulary. Their castles were built over three 40-minute class periods. We started with a very generic paper stencil and rolled out slabs of clay with my very beat-up rolling pins. After cutting notches for stairs and crenels at the top, they used wood blocks to create the brickwork and arrowloops on the castle. After rolling the clay up around a paper towel tube, they added their own creative touches. More than one added 'iron' prison bars to the exterior, one made a princess in distress, and one even made a miniature prisoner forever entombed in his clay project.
To give credit where credit is due, this idea came from a pin and we modified it to make it our own, prisoners and all.