To me, one of the most fascinating aspects of studying Grosseteste is that he wrote about both theology and science (in the medieval sense). The first-time, non-medieval reader is quick to ask herself whether Grosseteste had some split-brain features; after all 
religion and science often take opposing stances in contemporary debates. As Giles Gasper mentioned in his conference presentation at Porto, Grosseteste didn’t comment explicitly on how he saw the relationship between these two areas of interests. However, the scholars explained that in medieval times there was not yet the conceptual divide between religion and science. Instead, the elucidation of natural phenomena was thought of as giving depth to the wonders of God’s creation. Nonetheless, it is striking that Grosseteste, who was to become bishop of Lincoln later on, didn’t explicitly frame his scientific treatises in theological terms. Nonetheless, under closer inspection of the De luce, there are some references and fundamental assumptions that seem to hint at his theological commitments.
First, I had been wondering how Grosseteste arrived at the idea that light is key to extended matter, a connection that to me as a non-physicist seems almost far-fetched. In relation to this, Faith Wallis put forward the very intriguing
suggestion that the De luce may be concerned with the first day of creation in Genesis, when ‘God created the heavens and the earth. And the earth was without form, and void; and darkness was upon the face of the deep. […] And God said, Let there be light, and there was light.’ (Genesis, 1:1-3). The creation account reports that first ‘earth was without form’, i.e. dimensionless, and then light was introduced. Based on this order, it seems to be a reasonable assumption that it was from biblical inspiration that Grosseteste arrived at the key role of light in his cosmology. The resonance with the modern idea that light waves keep atoms from collapsing would be intriguing yet merely incidental.
Also, although theological references do not feature heavily in the De luce, Grosseteste refers a couple of times to an ‘incorporeal motive power’ of an ‘intelligence or soul, which moves the first and highest sphere with diurnal motion.’ (Neil Lewis’ translation, 177-180). Subsequently, Grosseteste uses the expressions ‘mover of the first heaven’, ‘first motive power’ and ‘intellective motive power that in incorporeally casting its mental gaze back over itself rotates the spheres with a corporeal revolution.’ (184, 185, 199-201). These references make quite clear that Grosseteste saw God at the core of his cosmology, and that he saw no conceptual conflict between a prime mover rotating the heavens and his scientific explanations of how lux and lumen give rise to the multitude of celestial and terrestrial spheres.
Furthermore, it is in itself telling that Grosseteste gave an account of origin for the Aristotelian universe. While Aristotle had thought of a steady-state cosmos, this was unsatisfactory to Grosseteste as a Christian theologian. Therefore, he set out to explain how the cosmos was created, and by doing so he went back to key ideas in Genesis and the concept of the prime mover.
To me it has been inspiring to see how historical traces of both theology and science converge in one and the same person. In harmony with the interdisciplinary spirit of the Ordered Universe Project this raises hope for more collaboration and less antagonism between science and religion.
Ulrike