The text of the poem...
The cast of characters found in Geoffrey Chaucer's General Prologue to The Canterbury Tales are not all connected except by their goal and their destination. Each of the twenty-nine characters who have gathered at the Tabard Inn in Southwark are going on a pilgrimage.
The text of the poem tells us that in April, the time when spring is showing signs of life everywhere in nature,
Then do folk long to go on pilgrimmage,
And palmers to go seeking out strange strands,
To distant shrines well known in sundry lands.
And specially from every shire's end
Of England they to Canterbury wend,
The holy blessed martyr there to seek
Who helped them when they lay so ill and weal.
This diverse assortment of sinners and saints is part of many groups who are making their way to Canterbury, a notable place because the highest-ranking Catholic church official in Britain, the Archbishop of Canterbury, is at this church. While Canterbury was always a popular destination for pilgrimages, even from medieval times, it became even more so after the death of Thomas Becket.
Becket was the Archbishop of Canterbury during the reign of Henry II (a Tudor king), and the two men were once great friends; unfortunately for both men, the king (Henry II) and the church (Becket) developed a combative relationship. Eventually Becket is brutally murdered and becomes a martyred saint. People began coming to Canterbury to visit his shrine. First they pray to him; then, when they are able, they come to pay tribute to him for helping them ward off evil and bringing them good luck.
So, these pilgrims are wending their way to Canterbury and have all stopped at this inn together. Their host soon makes them an offer which will unite them further as they make their way to the holy shrine.