to entertain
Puppets are used primarily for entertainment. Puppets can be used for all ages, from infants to kids to adults. They have been a popular form of entertainment for many years.
Castles in the Middle Ages were used to keep out enemies.
See the question: What are some weapons used in the middle ages?
In the Middle Ages
people in the middle ages used letters or talking to face to face
because they used wood smoke as a deorderant in the middle ages
knights
YES
Yes, polyphony was used during the Middle Ages. We do not have any real idea of when polyphony was introduced, but the earliest texts describing it date to the Early Middle Ages. By the end of the Middle Ages, it was highly developed. There is a link below to an article on polyphony, beginning at the section on its origins.
It was used in the middle ages by monks!
the middle ages
The predominant staircase design in the Middle Ages was the spiral design for stairs. Spiral stairs were used from the medieval ages and are still used in many modern houses.