Etymonline: aim (v.), c. 1300 — “to estimate (number or size), calculate, count.” Senses now obsolete. The word that became “to direct a missile” started as “to reckon the value of.” DMLBS gives aestimare sense 2c: “to intend” — the hinge between the accountant’s sum and the archer’s eye.
Which didst the signal aim To our hid forces!
— Drayton, “Agincourt” (1597)
The word is doing its old work here: Erpingham doesn’t shoot anything, he estimates — reads the field, judges the moment, assigns a value to silence and concealment. The aim precedes the archery. Then the stanza breaks and the arrows come, cloth-yard long, and suddenly the word belongs to the bowmen too. Drayton doesn’t use aim again, but the poem earns both senses from one instance — first the accountant’s reckoning, then the archer’s release. The hinge aestimare described, Drayton walks across without pausing.