The site of Crichton Collegiate Church may have been the location of an old Christian shrine. In about 1440 William Crichton, 1st Lord Crichton, Lord Chancellor of Scotland started to build a church there. On 26 December 1449 he opened the church. Like many other collegiate churches, Crichton was built for the use of the local lord, and a provost, eight prebendaries, two choir boys and a sacrist were appointed to pray for the souls of the Crichton family. The provost was granted the tiends and tithes of the prebends, the Rectory of Crichton and the Temple lands appertaining to Crichton.
The church was built in a Gothic and Romanesque cruciform style with a large central tower; the nave was used as the place of worship for the poor people. However the Crichton family supported the claimant Alexander Stewart, Duke of Albany, in the 15th century, fell out of favour with the Scottish Crown and the Crichton lands were forfeited. During the Scottish Reformation of 1560 the glass was taken from the windows, the floor converted back to earth and the medieval stone tracery destroyed. The chancel roof was still extant but the church was a ruin and considered unusable for services.
By 1569 it was being used as the parish kirk (church) and a minister, Adam Johnston, was ordained to lead the service. By the 1580s, major restoration work began, though the nave was said to be ruinous, as it is to this day. In 1641, by an Act of Parliament, Crichton Church was declared to be the parish church for all time. Though there was more restoration and adaptation in 1729 it was considered to have been carried out 'badly'. More work in the 1820s helped to bring the old church back to life, but it was not until the end of the 19th century that the church was fully restored, by the Edinburgh architects Hardy & Wright. Stained glass windows made by the Edinburgh company Ballantine and Gardener, new oak pews and a pipe organ built by the Glasgow company Joseph Brook were installed. The Church of Scotland closed the church in 1992 and the Crichton Collegiate Church Trust acquired the property. The Trust restored the organ, stained glass windows, lighting and the tower.
References:Sigmaringen Castle was first mentioned in the year 1077 in the chronicles of Petershausen monastery. The oldest parts of the castle are concealed beneath the alterations made during the 17th and the 19th centuries. The secret of the earliest settlement built on this defendable rock will never be fully revealed: large-scale excavation work would be necessary, which the extensive land development renders impossible. Judging from the many Roman remains unearthed in the area around Sigmaringen, the 12th century keep known as the 'Roman Tower' could be traced back to a Roman predecessor.
The castle remains that have been preserved (gate, great hall and keep) date back to the Staufer period around 1200. The castle remains were integrated into subsequent buildings. The foundations of the castle buildings are to a large extent identical to the surrounding castle wall.
These remains give us a good idea of how the castle might have looked during the 12th century.