Neville Letters: Vehemency and Celerity

On 28 August 1600, Neville wrote from London:

Prosecute those Things which you have in charge, with such Vehemency and Celerity, as conveniently you may. (Winwood's Memorials, 1.248)

Both words don't appear in pre-1599 plays but they do appear in 1599 and after. Once again, neither word is particularly uncommon. But we can date its entry into the canon roughly in-line with its use in a Neville letter. "Celerity" in particular is a French borrowing; perhaps it's a word he started to use in France.

Nay, I prithee now, with most petitionary vehemence, tell me who it is. As You Like It, 3.2

Would it apply well to the vehemency of your
affection, that I should win what you would enjoy? Merry Wives of Windsor, 2.2

Stands without blemish. Next, it imports no reason
That with such vehemency he should pursue Measure for Measure, 5.1

Fail not to use, and with what vehemency
The occasion shall instruct you Henry VIII, 5.1

Thus with imagined wing our swift scene flies
In motion of no less celerity Henry V, 3.0

Ay, with celerity, find Hector's purpose
Pointing on him. Troilus and Cressida, 1.3

Hence hath offence his quick celerity,
When it is born in high authority: Measure for Measure, 4.2

Than let him so be lost. O most kind maid,
It was the swift celerity of his death, Measure for Measure, 5.1

she hath such a celerity in dying. Antony and Cleopatra, 1.2

Celerity is never more admired
Than by the negligent. Antony and Cleopatra, 3.7