Stated in general terms, the property of foreigners have, since at least the early twentieth century enjoyed protection under international law from unacceptable measures of the host State. While the scope and contents of the rules and principles of international law in this respect were unclear, these rules and principles were collectively referred to as the "international minimum standard."
Kaj Hobér, Investment Treaty Arbitration and Its Future -- If Any, 7 Y.B. Arb. & Mediation 58 (2015).