Mistress;" the third part "Pindaric Odes;" and the fourth and last
his "Davideis."

In September of the following year, 1657, Cowley acted as best man
to George Villiers, Duke of Buckingham, on his marriage at Bolton
Percy, to Fairfax's daughter; Cowley wrote also a sonnet for the
bride. In December he obtained, by influence of friends, the degree
of M.D. from the University of Oxford, and retired into Kent to
study botany. Such study caused him then to write a Latin poem upon
Plants, in six books: the first two on Herbs, in elegiac verse; the
next two on Flowers, in various measures; and the last two on Trees,
in heroic numbers:- "Plantarum, Libri VI."

After the death of Cromwell, Cowley returned to France, but he came
back to England in 1660, when he published an "Ode on His Majesty's
Restoration and Return," and "A Discourse by way of Vision
concerning the Government of Oliver Cromwell." He was admitted, as
Dr. Cowley, among the first members of the Royal Society then
founded; but he was excluded from the favour of the king. He had
written an "Ode to Brutus," for which, said his Majesty, it was
enough for Mr. Cowley to be forgiven. A noble lord replied to
Cowley's Ode, in praise of Brutus, with an Ode against that Rebel.
Cowley's old friend, Lord Jermyn, now made Earl of St. Alban's,
joined, however, with George Villiers, Duke of Buckingham, in
providing for the poet all that was required to secure to him the
quiet life that he desired. Provision to such end had been promised
him both by Charles I. and Charles II., in the definite form of the
office of Master of the Savoy, but the post was given by Charles II.
to a brother of one of his mistresses.