When do people "long to go on pilgrimages"
The answer to your question is given in the very first line of the General Prologue to Chaucer's Canterbury Tales. It is in April that folk longen to goon on pilgrimages. Chaucer's Middle English is a little hard to understand, but it is a pleasure to read after you get used to it. Here is a sample from the General Prologue. The word "soote," meaning "sweet," would be pronounced with two syllables and sound like "so-tah." The word woold rhyme with "roote" at the end of the second line and would sound like "row-tah " People who long to go on trips in April are attracted to Canterbury Cathedral because of the beautiful countryside and the grandeur of their destination. The most beautiful lines in this passage would sound more or less like:
And small-ah fowl-less mockenmelodie
That slepenoll the nicht with open ee.
Here are the opening lines of The Canterbury Tales:
Whan that aprill with his shoures soote
The droghte of march hath perced to the roote,
And bathed every veyne in swich licour
Of which vertu engendred is the flour;
Whan zephirus eek with his sweete breeth
Inspired hath in every holt and heeth
Tendre croppes, and the yonge sonne
Hath in the ram his halve cours yronne,
And smale foweles maken melodye,
That slepen al the nyght with open ye
(so priketh hem nature in hir corages);
Thanne longen folk to goon on pilgrimages,
And palmeres for to seken straunge strondes,
To ferne halwes, kowthe in sondry londes;
And specially from every shires ende
Of engelond to caunterbury they wende,
The hooly blisful martir for to seke,
That hem hath holpen whan that they were seeke.
Anyway, the time is April, the beginning of spring. The long, cold winter is over and people want to get outdoors to enjoy the beauty of nature.