Nature and God I neither knew — Venus

The name Herschel hints at something related to astronomy, and Mercury's affair with Venus tells the answer. The narrator is Venus.

Nature and God－I neither knew ¹
Yet Both so well knew me
They startled, like Executors
Of My identity.

Yet Neither told－that I could learn－⁵
My Secret as secure
As Herschel's private interest
Or Mercury's affair－

(F.803/J.835)

[1] Nature and God:: People in the earth and God.
[2] well knew Me:: people knew the planet Venus.
[4] My identity:: Venus appears before sunrise or after sunset. It's called the Morning Star or Evening Star.
[6] Secret:: Venus' two identities.
[7] Herschel:: Caroline Herschel (1750-1848), whose private interest in astronomy made her famous.
[8] Mercury:: In Greek myth, Mercury had an affair with Venus.