Since the late 1980s, the chapel has been the subject of speculative theories concerning a connection with the Knights Templar and the Holy Grail, and Freemasonry.

The chapel is dedicated to Saint Matthew the Evangelist and was founded on a small hill above Roslin Glen as a collegiate church (with between four and six ordained canons and two boy choristers) in the mid-15th century.

During this period, the rich heritage of plainsong (a single melodic line) or polyphony (vocal harmony) were used to enrich the singing of the liturgy.

[5] The chapel was rededicated on 22 April 1862, and from this time, Sunday services were once again held, now under the jurisdiction of the Scottish Episcopal Church.

[15] In 2006, historian Louise Yeoman criticised the Rosslyn Chapel trust for "cashing in" on the popularity of The Da Vinci Code, against better knowledge.

[18] The original plans for Rosslyn have never been found or recorded, so it is open to speculation whether or not the chapel was intended to be built in its current layout.

[2] The chapel stands on fourteen pillars, which form an arcade of twelve pointed arches on three sides of the nave.

At the east end, a fourteenth pillar between the penultimate pair form a three-pillared division between the nave and the Lady chapel.

According to the legend, the master mason did not believe that the apprentice could perform the complicated task of carving the column without seeing the original which formed the inspiration for the design.

The legend concludes that as punishment for his crime, the master mason's face was carved into the opposite corner to forever gaze upon his apprentice's pillar.

[25] On the architrave joining the pillar there is an inscription, Forte est vinum fortior est rex fortiores sunt mulieres super omnia vincit veritas: "Wine is strong, a king is stronger, women are stronger still, but truth conquers all" (1 Esdras, chapters 3 & 4).

[26] The author Henning Klovekorn has proposed that the pillar is representative of one of the roots of the Nordic Yggdrasil tree, prominent in Germanic and Norse mythology.

[27] The general form of the pillar has been related to a type described by the French architect Eugène Viollet-le-Duc as a "bunch of sausages.

[29] Among Rosslyn's many intricate carvings are a sequence of 213 cubes or "boxes" protruding from pillars and arches with a selection of patterns on them.

This crypt has been sealed shut for many years, which may explain the recurrent legends that it is merely a front to a more extensive subterranean vault containing (variously) the mummified head of Jesus Christ,[37] the Holy Grail,[38] the treasure of the Templars,[39] or the original crown jewels of Scotland.

Exhaustive searches over the period of a week were made, but no entrance to the original vault was found and he was buried beside his wife in the Lady Chapel.

[45] The topic entered mainstream pop culture with Dan Brown's The Da Vinci Code (2003), reinforced by the subsequent film of the same name (2006).

[46] Numerous books were published after 2003 to cater to the popular interest in supposed connections between Rosslyn Chapel, Freemasonry, the Templars and the Holy Grail generated by Brown's novel.

An example is the comparison of the Rosslyn myth of the Apprentice Pillar with that of the allegorical references to Hiram Abiff in Masonic ritual, and in the process he debunks any similarities between the two.

If you superimpose the floor plans of Rosslyn Chapel and either Solomon's or Herod's Temple, you will actually find that they are not even remotely similar.

[...] If you superimpose the floor plans of Rosslyn Chapel and the East Quire of Glasgow Cathedral you will find a startling match: the four walls of both buildings fit precisely.

The East Quire of Glasgow is larger than Rosslyn, but the designs of these two medieval Scottish buildings are virtually identical.

Andrew Kemp noted that 'the entire plan of this Chapel corresponds to a large extent with the choir of Glasgow Cathedral' as far back as 1877 in the Proceedings of the Society of Antiquaries.

[34] Historian Dr. Louise Yeoman, along with other medieval scholars, says the Knights Templar connection is false, and points out that Rosslyn Chapel was built by William Sinclair so that Mass could be said for the souls of his family.

This may have taken place in the 1860s when James St Clair-Erskine, 3rd Earl of Rosslyn instructed Edinburgh architect David Bryce, a known Freemason, to undertake restoration work on areas of the church including many of the carvings.