11 12 15 1766-1841 19thcentury 6 ancient art artthefts athens classicalantiquitiesthefts culturalproperty ethicselgin exhibitiontechniques foreignrelations greatbritain greece greece) greek history historybritishmuseum lf1800 marblesculpture nb92 parthenon(athens protection publicopinion repatriation restitution sculpture thomasbruce