This article is a comparative elaboration of Eugene Hammel's pioneering analysis of “fictive kinship,” Alternative Social Structures and Ritual Relations in the Balkans (1968). In place of godparenthood, I examine the structurally similar institution of fosterage or “milk kinship” as documented in former mountain kingdoms of the Hindu Kush in northern Pakistan. Comparable structures of interdomestic allegiance and tributary patronage organized through milk kinship are attested more fragmentarily elsewhere in the Middle East and Central Asia, and there is further evidence that such hierarchized foster relations also extended into many peripheral regions of premodern Europe (E. Goody 1982:280–1; Parkes n.d.). Hammel himself mentioned Serbian “kinship by milk” (srodstvo po mleku)—“meaning the fictive kinship relationship between two children suckled by the same woman, but otherwise unrelated” (1968:31 n.27)—with reference to Filopovich's (1963) earlier survey of South Slavonic ritual kinship. Yet Hammel did not pursue the possible analogies of such fosterage ties with kumstvo godparenthood: as structurally equivalent institutions of constructed kinship, once orchestrating transitive chains of interdomestic allegiance and tributary governance in peripheral polities throughout Eurasia.