Of the two values of ancient objects, the connoisseur's first concern is with the object today, and the archaeologist's is with its past place and the knowledge it offers about the past. Central to both is provenance, which comprises the ‘archaeology’ of the item - its story until it went to rest in the ground - and its ‘history’ - its story once found and brought to human awareness again. Our response to looting of antiquities depends on how serious is the impact on knowledge, so we need a ‘quantitative history’ of collecting - how much there was to start with, how much has been dug up, how much we know about it, how much remains. Four quantitative histories are reported: on Cycladic figures, on items in recent celebrated classical collections, on antiquities sold at auction in recent decades, and on classical collecting at the Ashmolean Museum, Oxford. These pioneering studies are not yet enough to make a clear overall picture; our preliminary conclusion is a glum view of the damage caused by the illicit pursuit of antiquities.