One of the bedrock principles of the Durham Grosseteste Project is the activity of collaborative reading. It sounds simple, and it many respects it is, but sitting together, to read through a text, slowly and thoughtfully, creates the environment in which exciting and imaginative ideas for research take shape and evolve. All present are able to askquestions or to ask for explanation, and we have run these sessions as openly as possible, with a wide range of observers and participants from across Durham and other institutions, along with the core team.
This then, we did for our afternoon session on the workshop, taking as our texts the treatises on Colour, on Light and on the Rainbow. I was struck again at the abstract complexity of Grosseteste’s investigation of colour; with three axes of opposites – copious or scarce light, dim or bright and a pure or impure medium, within the two extremes of whiteness and blackness. The group discussion brought out the dynamism of Grosseteste’s thinking, the movement by ascent from blackness and by descent from whiteness. We examined the passages concerning the creation of the nine celestial spheres in the treatise on light, the notion of the crystalline spheres deriving from Aristotle, the 
sequence of nine, and then the sub-lunar spheres, which would dominate western thinking derives from Arabic commentary of the earlier Middle Ages, especially that by al-Farabi. Finally the rainbow treatise allowed the experiments outlined earlier by Brian to be seen in their context, as part of the arguments Grosseteste adduces for how the science of the rainbow is best to be approached, why Aristotle did not delve into the matter in a more complete manner, and how perspective, optics and physics are all needed to address the issue. We made a foray into the complexities of the rainbow diagram (which have puzzled the team for some time), and then explored, with Hannah’s help, the relation between the colour sequence at the end of the rainbow, with that of the earlier text on colour.
So, needing to put brains out to pasture for a while, the next item on the agenda was the first show of the 3D visualisation, put together by Nick Holliman, with help from Adam Harries. The first half of the film is prepared, in a 2D format, with voiceover by Sally Hodgkiss, a Durham alumna in Linguistics and now actor. A second voiceover has been recorded by Sir Thomas Allan, the University Chancellor. 
Richard Bower introduced the film, with a survey of modern cosmological thinking, and then how thedifficulties of Grosseteste’s expanding and then contracting universe were encountered and solved. The effort to translate Grosseteste’s text into representational mathematics, to render in two dimensions, and then in three, speak to the power of this 13th century text to speak to modern scientists and to stimulate creative responses, which pose questions to 21st century cosmology and computer-assisted ingenuity. The 
film was extremely interesting to see: artistic licence aside, I was left pondering the extent to which this was something Grossteste would have recognised, and what his responses would have been. To be able to conjure an imagined reality is a wonderful interpretative tool to have at our disposal, as well as a culturally approachable form in which to showcase the results of our collaborations.
After all of these exertions a visit to the surroundings of Durham Castle, aka University College, and the Norman Chapel – one of the earliest stone built Norman buildings surviving. Which seemed a very fitting end to the day.