The word abbey means father. This is because the abbot is the 'father of the monks'. Abbeys were important buildings where abbots were in charge of monks.
Abbeys are among the oldest Christian buildings ever built. The first Christian monks were hermits, and in fact the word 'monk' means 'to be alone'. However, some monks became famous for their holy powers, and started attracting followers. As increasing numbers of people wanted to become monks, an organised way of doing things developed, and communities of monks were set up, each headed by an abbot.
The monks were often showered with gifts, as it was believed that the giver would be blessed for their generosity. However, the monks soon became targets for thieves. To combat this, communities of monks started to live in buildings with high walls, and these developed into what we call monasteries. The buildings were often arranged around an open courtyard surrounded by covered walkways. This is called a cloister.
The monastery was a community, made up of lots of buildings. These included storehouses, kitchens, dormitories to sleep in, places to eat and small places to pray. In the middle of all of this was the large church where everybody gathered. It was called the Katholikon, and this is what we call a cathedral today. The word cathedral has always been used to mean 'the most important church'