The concept of chilvalry is most important in my understanding of the Medieval Romance. Knights are supposed to be devoted to women and in their behaviour must be respectful, courteous, and helpful, especially if women are facing problems or danger and need help to be rescued or some kind of assistance. This is of course linked to the last point made in the above post as total and complete devotion is a natural outcome of a chivalrous spirit.
There are numerous elements common to the medieval romance. Depending on who you ask and where you look, you may find different answers, but there are four elements that are found pretty much across the board.
First, medieval romances idealize chivalry. The heroes always manifest the qualities of a kind, self-less and charitable knight.
Secondly, most medieval romances have a vague or even sometimes imaginary setting. The romance is TRULY the center of the story, so where it takes place isn't as important. The lack of actual setting also allows the reader to more easily but him or herself in the situations.
Third, medieval romances rely on elements of the supernatural to create mystery and suspense. Whether it's a mystical creature, and supernatural setting, or seemingly normal characters possessing one strangely supernatural quality, this element is key in this type of literature.
Lastly, and argueably most importantly, is the element of the romance. The knight's love for his lady - a love of complete and total devotion - is what drives medieval romances throughout.