13 carved busts have ringed the perimeter of the Sheldonian Theatre since 1669. Twice the Heads have been replaced when deteriorated beyond recognition. The second generation were damaged by the polluted atmosphere of coal-fuelled Victorian Oxford and these effects were exacerbated by a choice to carve in Milton limestone. Before they were replaced, the Ministry of Public Building and Works purportedly undertook conservation trials on three Heads. Due to poor record-keeping, it is unclear which of the three Heads, held by Worcester College, Oxford, used in the strengthening trials were treated in which manners. We aim to measure the internal morphology and approximate composition of a series of samples taken from the 3 heads to quantitatively characterize and contrast the level of weathering and to determine which of the heads was treated with which conservation method.