Llantwit Major, or otherwise known as Llanilltud Fawr, has been occupied for over 3000 years. Bronze Age and Iron Age people, and the Romans lived here before the Celtic Church made this a place of national importance, but the oldest buildings now seen in the town were built by the Normans.
The town square has at its centre an old preaching cross, which is now the war memorial. Around it is a group of Tudor buildings, built when the town had to be rebuilt following a visit with fire and sword by Owain Glyndwr shortly after 1400.
About 1440, a new family came to Llantwit Major, the Raglans or Raglands. Robert Raglan built a house which is otherwise known as the Old White Hart public house, which makes it the oldest continually inhabited house in the town. Around 1465, Raglan built a new house, which in time was used by the church as a presbytery, and which in 1874 was extended and became the village school, now the "Old School" used by community groups. The Old Swan Inn on the other side of the square is another Raglan house. There is a tradition that this pub was at one time a mint.
St. Illtud's Church, which was described by described by John Wesley in 1777 as "the most beautiful as well as the most spacious church in Wales", has a very long history. Christ has been worshipped here for about 1500 years, since Illtud came here and, by the side of the Ogney Brook, established a church, monastery and school. It became the burial place of local kings and an important mission centre. It contains one of the most significant collections of Celtic stones in Wales.