You may have often seen the symbol below around your church:
On first glance it looks like an "X" and an "P". In reality, it is the greek letters "chi" or χ and "rho" or Ρ. These are the first two letters of the greek word "christos", which means "Christ".
Back in the time of the Roman Empire, Emperor Constantine had a dream. He dreamed that if he placed these two letters in the banners ahead of him in battle, he would win. He tried it, and he did win the battle. This victory was one of the experiences that opened him up to Christianity and helped led him to making it the official state religion of the Roman Empire.
Next time you go into church and see this symbol, you will no longer see just a "P" and an "X". Now you will see a symbol of Christ the Victor and a reminder of the role of Constantine in the spreading of our faith.