Various critics and biographers, such as Piglia and Williamson, have focused on the way in which Borges tends to view national history in terms of his own family history, and an opposition between the paternal and maternal family lines. John King puts it succinctly:

King is simplifying a little, by immediately associating the military with barbarism and only one side of the family with the military, but nevertheless the opposition stands. Alan Pauls has recently given a snappy formulation of one of the major structures of Borges's world. Most oppositions in his work are subsumed into the category of the duel, seen as the very DNA of his prose: ‘The duel – but also, in their way, battles, crime, chess and, especially truco [a River Plate card game] – is like the chip of Borges's fiction, its DNA, its finger print.’ Borges's first narrative, ‘Hombres pelearon’, ‘Men Fought’, published in El idioma de los argentinos (1928), was the story of a duel, and was rewritten, in different keys, over many years until ‘The Story from Rosendo Juárez’, in Brodie's Report, El informe de Brodie (1970). The theme covers many literal duels and rivalries between men, often rewriting literary texts such as Martín Fierro, and historical encounters, as between San Martín and Bolívar in ‘Guayaquil’. The structure also articulates the tension between conceptual oppositions such as time and eternity, Platonism and Aristotelianism. The family theme is, in a way, one aspect of the general duel structure.

Borges's interest in his ancestors begins strictly with the independence struggle of Argentina from Spain, and he petulantly dismisses anything before as pre-history. In the 1967 interview with Jean de Milleret, he asserts: