I am used to the idea of five being associated with human life and St Bonaventure for example, makes this connection in describing the five corporal senses and the five spiritual senses of man. Given that Our Lady who gave, so to speak, Christ his humanity, the linking of Our Lady to the number five does seem to be a natural extension of this, but if this extension had been made in the past one would have thought that there would reference to it somewhere in the writings of the saints. Similarly, we know from historical documents that gothic masons used geometry in the design of their cathedrals (Milan Cathedral is designed on a triangular grid, for example). I have heard of no similar document making the connection between a building dedicated to Our Lady and a pentangular design, although I have heard similar claims about other buildings such as the rose window at the gothic cathedral at Amiens dedicated to Our Lady - 'Notre-Dame d'Amiens' (shown above). There is every chance of course that these records do exist and it is simply that I do not know about them, so I keep an open mind.
Suppose, for arguments sake that we can find no real justification for concluding that there is a historical connection between the number five and Our Lady, and that the examples listed are to be considered just coincidences - after all you have to pick some sort of symmetry in a well ordered design. Does this mean that we can't make the association now? In my opinion, the answer to that is no. There seems to be logic behind the arguments for the connection, so even if the connection wasn't made in the past, we can make that connection now. If a tradition is to be a genuinely living tradition, it has to allow for development in the present. It cannot only be about reestablishing what was done in the past.
Then, assuming that we make the connection even if we assign five to the Blessed Virgin, what do we do with it? Why bother to do such a thing? This brings us down to the fundamental question as to the purpose of such symbolic numbers. There are different reasons why they are useful. Sometimes is allows for a deeper interpretation of scripture and St Augustine especially was very interested in this.
Also we can order time and space according to it. Number has a special property in that it can be both conceived in the abstract and then assigned to matter and time. In this sense it occupies both the material world and the world of ideas (or perhaps more accurately the 'immaterial' world). We can order time and space in accordance with it, for example designing a work of art, or the dimensions of a building, or even a cycle of prayer around fivefold symmetry, five relative units of length, or five repetitions respectively.
There is an important point to make in regard to this: the symbolism is not arbitrarily assigned. If there is anything to it all it is because the number symbolism reflects and reveals some underlying truth, and so helps us to understand better (sometimes at an intuitive level) what it is pointing to. This being so, when we design a window, for example, that is based around an image or theme of Our Lady and if the number five is truly symbolic of her, then the window will be more beautiful and suited to its purpose in all ways if its design is ordered to it - a fivefold symmetry, for example. One of the attributes of beauty listed by St Thomas is 'due proportion'. The argument here would be that ordering the design of things associated with Our Lady to the number five is appropriate or 'due'. In another recently posted article I argued, here, that the octagonal design, linked to the symbolism of eight as the eighth day of creation, in Raphael's Mond Crucifixion contributed significantly to its beauty and its effectiveness as a work of art. This is true, and here is the important point, regardless of whether or not the viewer is conscious of the design feature or of the symbolism. In the case of the Raphael, I was attracted by the beauty of the painting long before I noticed this design feature. Once I had noticed it, it gave me greater understanding of Raphael's methods, but did not change one iota my appreciation of his painting.
If we forget this and are not discerning in our interpretation and application of these numbers, there is a real danger that the whole topic degenerates into a game in which the initiated communicate with each other via a secret language. Some who I have met do treat this as a secret knowledge that only those who are ready may know. This strikes me as a modern day Gnoticism that is to be discouraged.
My introduction to these ideas came through people who, despite their great interest in tradition, subscribe to a philosophy they called perennialism or universalism, which as I understand it gained popularity in the 20th century. As far as I was able to grasp their position, they maintain that the major religions are equally valid revelations by God to different cultures. This meant the people I met were always looking for elements common to all as the basis of truth. While I am grateful for the work these people have done in showing me and many others aspects of my own tradition that I would very likely not have known otherwise, I am wary in accepting uncritically any interpretations they give. I try to seek authenticatification from a Catholic source, such as the writings of a Church Father, before wholeheartedly embracing it.
As to whether or not I will use fivefold symmetry in paintings of Our Lady? I need to think about it and perhaps give it a try, and see how it turns out.
A plan of the Lady Chapel at Wells Cathedral (the alcove top, centre in the diagram). The furthest three facets do correspond, within the bounds of accuracy of working in such a diagram, to part of a pentagon.
The path traced by the planet Venus across the night sky. This diagram comes from a modern analysis. Some may question to as to whether this would have been known by the classical world or the medievals. I do not know, but think it is possible. The reason that Venus, which would otherwise be another bright light in the sky, was differentiated from the other stars is that it appeared to move independently of the rest of the stars, which all moved together as a single canopy rotating around the pole star. If they could distinguish Venus as being different, then I would imagine that they studied its motion across the sky with great precision.