Drumbo Round Tower lies within the grounds of the local Presbyterian church. Historically the tower was attached to a medieval parish church and monastery, the foundations of which can be seen in the modern day graveyard on the site.
The tower dates from around the early medieval period and is a scheduled historic monument. The original structure was severely damaged when the site was plundered by Connor, son of Artgal McLochlin in 1130.
The site of the Drumbo round tower and medieval monastery is one of the oldest religious foundations in Ireland. In the life of Saint Patrick, which is contained in the Book of Armagh, the name Drumbo signifies 'the long hill of the cow,' which was translated into Collum Bovis, a name by which the ancient church was known. The round tower was originally built here to take advantage of the panoramic views over the Lagan Valley. At the time of the tower's construction, these views would have been useful in spotting incoming Viking raids.
The tower survives to a height of 10.7 metres. It is 5 metres in diameter, with an internal diameter of 2.75 metres. The wall is about 1.2 metres thick. The entrance in the east is 1.5 metres above ground level and is 1.68 metres high and about 0.56 metres wide. Inside there are beam holes indicating that the internal floors were of timber and there are six surviving levels including the basement.
References:Visby Cathedral (also known as St. Mary’s Church) is the only survived medieval church in Visby. It was originally built for German merchants and inaugurated in 1225. Around the year 1350 the church was enlarged and converted into a basilica. The two-storey magazine was also added then above the nave as a warehouse for merchants.
Following the Reformation, the church was transformed into a parish church for the town of Visby. All other churches were abandoned. Shortly after the Reformation, in 1572, Gotland was made into its own Diocese, and the church designated its cathedral.
There is not much left of the original interior. The font is made of local red marble in the 13th century. The pulpit was made in Lübeck in 1684. There are 400 graves under the church floor.