What came before 26 June 1284

Into the street the Piper stepped,
Smiling first a little smile,
As if he knew what magic slept
In his quiet pipe the while;
Then, like a musical adept,
To blow the pipe his lips he wrinkled,
And green and blue his sharp eyes twinkled
Like a candle flame where salt is sprinkled;
And ere three shrill notes the pipe uttered,
You heard as if an army muttered;
And the muttering grew to a grumbling;
And the grumbling grew to a mighty rumbling;
And out of the houses the rats came tumbling.
Great rats, small rats, lean rats, brawny rats,
Brown rats, black rats, grey rats, tawny rats,
Grave old plodders, gay young friskers,
Fathers, mothers, uncles, cousins,
Cocking tails and pricking whiskers,
Families by tens and dozens,
Brothers, sisters, husbands, wives—
Followed the Piper for their lives.
From street to street he piped advancing,
And step for step they followed dancing,
Until they came to the river Weser,
Wherein all plunged and perished!

The Rat-catcher arrived to the rats-infested Hamelin in June 1284. He was promised a handsome pay by the mayor to rid the town of rats with his pipe. He led the rats, playing his pipe, to the river Weser. Rats followed, enchanted, close on his heels and at the end of a cliff they all jumped into the river and drowned.
The Rat-catcher came to collect his dues. The town people refused to pay up... and the Rat-catcher left, calling:

"And folks who put me in a passion
May find me pipe to another fashion."

The town people still did not bend.

"You threaten us, fellow? Do your worst,
Blow your pipe there till you burst!"

The Rat-catcher returned to Hamelin on 26 June 1284 to do his worst.