RESEARCH: in the spirit of getting it out there, I've written something for a book on northern sanctity about how the phenomenon of saints exuding oil from their corpses happens weirdly late in England, and is confined to 5 male bodies from 1200 on in Yorkshire and Lincoln

On the Continent male episcopal saints tend to exude oil from their bodies 9th-12th C in imitation of St Nicholas. 12th-15th C it's mainly female saints in imitation of St Catherine

England bucks this trend, starting with St William of York in c. 1223. From there it spreads to St Robert of Knaresborough, St Hugh of Lincoln, Robert Grosseteste, and St John of Beverley, all in what I like to think of as the 'oily triangle'

Why? Oil is something only bishops can consecrate, so it represents independence from the diocesan (why rely on the bishop when your own dead and sainted bishop can make it for you?)

Also it provides a centrepiece for diocesan/regional communal gatherings at the cathedral/mother church at Pentecost

NB I wrote this for the brilliant 'Northern Lights' project at Lausanne, organised by Denis Reveney, Christiania Whitehead, and @MedievalHaze, and it was hands-down the best conference I've ever been to