In particular, a leaf of laurel placed under the pillow was believed to be a cure for failing inspiration: pure poetical Viagra. Sadly, this rarely helped the poets laureate, most of whom were written out even before taking on the role.
The story usually begins with Ben Jonson, given a pension by James I after he had written a number of flattering court masques. On Jonson's death in 1637, it was 16 months before Sir John Davenant, who lost his nose to disease at around the same time, was awarded the title. His devotion is an example to modern claimants: he fought for Charles I in the Civil War, nose or no nose, later re-emerging as laureate to Charles II. His poetry, though, was unreadable. It was only with John Dryden, in 1668, that the poet laureate became an established royal post. But Dryden backed the wrong side in the Glorious Revolution, and was summarily replaced by Thomas Shadwell, the start of a century of nonentities. Laureates were now obliged to produce odes at New Year and on royal birthdays, to be set to music.
Until the advent of Romanticism, poets wrote to order, and few proved averse to well-paid hack work. But then they discovered the need for inspiration and soon were unable to do that kind of thing at all. Bowing to the inevitable, Queen Victoria did away with all the obligations attached to the honour when appointing Wordsworth in 1843, three years before his death.
There is, however, still an expectation that the laureate will produce commemorative poems for royal and state events. Tennyson produced lots, but then he produced lots of everything. So did John Masefield, less convincingly.