Impurity of the land of the nations (Tumath eretz Ha'Amim טומאת ארץ העמים) is a rabbinic edict stipulating a specified degree of tumah (impurity) on all lands outside the Land of Israel. The demarcation lines of foreign lands effectually included all those lands not settled by the people of Israel during their return from the Babylonian exile during the Second Temple period, and was meant to dissuade the priests of Aaron's lineage from venturing beyond the Land of Israel where graves were unmarked, and who may inadvertently contract corpse uncleanness and thereby eat their bread-offering (Terumah), unawares, in a state of ritual impurity and becoming liable thereby to kareth. The declaration with respect to foreign lands includes also the "virgin soil" of those lands, and was, therefore, a