Rugby is a full-contact team sport believed to have been invented in 1823 by William Webb Ellis. It is played between two teams of 15 players on a grass field with H-shaped goal posts at each end, where players can score points by grounding the ball over the goal line for a try, drop kicking, or penalty kicking the ball between the posts. Teams compete to outscore each other by running with, kicking, or throwing the ball forward within the 80-minute match consisting of two 40-minute halves.