Believe it or not in the early days of hockey it was against the rules for goalies to fall to the ice to stop the puck! They were to remain standing at all times, and were subject to a minor penalty at the referee's discretion if they did fall to the ice. There are even some reports of goalies who were fined a whole $2 for the foul.
The National Hockey League changed the rule in 1917-18 season, thanks in large part to an Ottawa goalie named Clint Benedict. Benedict made an art out of the accidental fall on the puck. He spent so much time on his knees on the ice that he quickly earned the nickname Praying Bennie!
He also publicly admitted that "if you did it a bit sneaky and made it look accidental, you could fall on the puck without being penalized." These comments made NHL rule makers aware of the problem and from that point on goaltenders were allowed to fall to the ice to stop pucks.
Benedict was a highly influential goalie of his time. He actually wore the first mask in NHL history, not Jacques Plante as is popularly believed. He was also one of the earliest star goalies, playing an amazing 17 seasons and winning 4 Stanley Cups. As such he became the hero so many young goalies wanted to become themselves one day.