After Aeneas has been revealed to Dido and has identified himself, she is in awe of the man, dumbstruck with wonder:
Obstipuit primo aspectu Sidonia Dido,
casu deinde viri tanto, et sic ore locuta est. (1.613-14)
The first word of the line assimilates her to Aeneas, who, when he saw that many of his companions had survived, was described thus:
Obstipuit simul ipse, simul percussus Achates
laetitiaque metuque… (1.513-14)
The similarity between the two passages is enhanced by what follows: in 517ff., a series of indirect questions (quae fortuna; quo litore; quid); in 615 ff., a series of direct questions (quis; quae vis; tune ille…).
The assimilation, though, is unsettling, for that first word, obstipuit, and the further parallel of questioning make Dido and Aeneas seem much closer than they actually are: Aeneas was dumbfounded at the survival of his friends, men with whom he had been close for a long time. Dido has never seen Aeneas before, and thus has no real bond with him whatsoever, and the closeness she desires with him (signaled by the echo?) will prove to be her undoing. And indeed, it may be that Vergil alerts the reader to that very fact here. For, immediately after the echo of obstipuit, in the same line-initial position, the first words that follow in 613 are primo aspectu; Vergil reminds us that Dido has never laid eyes upon Aeneas before, and perhaps indicates that we should notice the inconcinnity of the two figures despite the verbal resemblance.