Many son-and-father stand behind Dante's encounter with Cacciaguida. He's certainly thinking of Phaethon's quest for knowledge of his father. And Brunetto Latini, Inferno 15, who, the poet says, taught come l'uom s'eterna (how man makes himself immortal) is highly relevant, if by contrast with the familial bond Dante discovers with Cacciaguida.
But the one that Cacciaguida's first words put before us is from Virgil. It's Aeneas's encounter with his father Anchises in the Underworld, Aeneid 6, 679 ff.
The long scene begins:
Perseus VI.679-703:
At pater Anchises penitus convalle virenti
680inclusas animas superumque ad lumen ituras
lustrabat studio recolens, omnemque suorum
forte recensebat numerum carosque nepotes,
fataque fortunasque virum moresque manusque.
Isque ubi tendentem adversum per gramina videt
685Aenean, alacris palmas utrasque tetendit,
effusaeque genis lacrimae, et vox excidit ore:
“Venisti tandem, tuaque exspectata parenti
vicit iter durum pietas? Datur ora tueri,
nate, tua, et notas audire et reddere voces?
690Sic equidem ducebam animo rebarque futurum,
tempora dinumerans” nec me mea cura fefellit.
Quas ego te terras et quanta per aequora vectum
accipio! quantis iactatum, nate, periclis!
Quam metui, ne quid Libyae tibi regna nocerent!”
695Ille autem: “Tua me, genitor, tua tristis imago,
saepius occurrens, haec limina tendere adegit:
stant sale Tyrrheno classes. Da iungere dextram,
da, genitor, teque amplexu ne subtrahe nostro.”
Sic memorans, largo fletu simul ora rigabat.
700Ter conatus ibi collo dare brachia circum,
ter frustra comprensa manus effugit imago,
par levibus ventis volucrique simillima somno.
More here and below
But the one that Cacciaguida's first words put before us is from Virgil. It's Aeneas's encounter with his father Anchises in the Underworld, Aeneid 6, 679 ff.
The long scene begins:
[679] But deep in a green vale father Anchises was surveying with earnest thought the imprisoned souls that were to pass to the light above and, as it chanced, was counting over the full number of his people and beloved children, their fates and fortunes, their works and ways. And as he saw Aeneas coming towards him over the sward, he eagerly stretched forth both hands, while tears streamed from his eyes and a cry fell from his lips: “Have you come at last, and has the duty that your father expected vanquished the toilsome way? Is it given me to see your face, my son, and hear and utter familiar tones? Even so I mused and deemed the hour would come, counting the days, nor has my yearning failed me. Over what lands, what wide seas have you journeyed to my welcome! What dangers have beset you, my son! How I feared the realm of Libya might work you harm!”
But he answered: “Your shade, father, your sad shade, meeting me repeatedly, drove me to seek these portals. My ships ride the Tuscan sea. Grant me to clasp your hand, grant me, father, and withdraw not from my embrace!” So he spoke, his face wet with flooding tears. Thrice there he strove to throw his arms about his neck; thrice the form, vainly clasped, fled from his hands, even as light winds, and most like a winged dream.
Perseus VI.679-703:
At pater Anchises penitus convalle virenti
680inclusas animas superumque ad lumen ituras
lustrabat studio recolens, omnemque suorum
forte recensebat numerum carosque nepotes,
fataque fortunasque virum moresque manusque.
Isque ubi tendentem adversum per gramina videt
685Aenean, alacris palmas utrasque tetendit,
effusaeque genis lacrimae, et vox excidit ore:
“Venisti tandem, tuaque exspectata parenti
vicit iter durum pietas? Datur ora tueri,
nate, tua, et notas audire et reddere voces?
690Sic equidem ducebam animo rebarque futurum,
tempora dinumerans” nec me mea cura fefellit.
Quas ego te terras et quanta per aequora vectum
accipio! quantis iactatum, nate, periclis!
Quam metui, ne quid Libyae tibi regna nocerent!”
695Ille autem: “Tua me, genitor, tua tristis imago,
saepius occurrens, haec limina tendere adegit:
stant sale Tyrrheno classes. Da iungere dextram,
da, genitor, teque amplexu ne subtrahe nostro.”
Sic memorans, largo fletu simul ora rigabat.
700Ter conatus ibi collo dare brachia circum,
ter frustra comprensa manus effugit imago,
par levibus ventis volucrique simillima somno.
More here and below