Why does the narrator start the poem with the celebrations in the month of April? What is the significance of this month in the context of the prologue and in Medieval times?

Read the lines below to help you answer the question Please.

11 (So priketh hem Nature in hir corages),
(So Nature incites them in their hearts),
12 Thanne longen folk to goon on pilgrimages,
Then folk long to go on pilgrimages,
13 And palmeres for to seken straunge strondes,
And professional pilgrims to seek foreign shores,
14 To ferne halwes, kowthe in sondry londes;
To distant shrines, known in various lands;
15 And specially from every shires ende
And specially from every shire's end
16 Of Engelond to Caunterbury they wende,
Of England to Canterbury they travel,
17 The hooly blisful martir for to seke,
To seek the holy blessed martyr,
18 That hem hath holpen whan that they were seeke.
Who helped them when they were sick.