These seals were used to distinguish government goods from those of private collectors. These are the earliest known "collection chops."
早在唐朝，太宗的「貞觀」二字連珠小璽、玄宗的「開元」小璽，就已經出現在御府收藏的圖書和器皿上，蓋印目的是表示這批文物為大唐御寶，有別於民間收藏，這算是「收藏印」的最早例證。