Complex sentence: Cloaks of invisibility are relatively rare in folklore; although they do occur in some fairy tales, such as "The Twelve Dancing Princesses", a more common trope is the "cap" of invisibility.
Split into simpler sentences: Cloaks of invisibility are relatively rare in folklore; although they do occur in some fairy tales, such as "The Twelve Dancing Princesses". A more common trope is the "cap" of invisibility.