During the reign of Queen Iris, there was a barren country to the northwest part of the continent of Equus, in the southwesternmost corner of North Griffonia. This barren area of land still holds an abandoned castle near the sea, with a cave on the beach below the cliffs holding it. In this castle, ruling this area, there lived a king.

It was said that he had probably been young at some point, but those of the time who knew him always knew him as an old creature, an equine of uncertain species, grey and lifeless, with eyes that did not seem to reflect light, instead taking it and hoarding it away somewhere within him.

He had a name, a name fitting his shabby, miserly appearance, and the appellation "Cursed King" was only gained later, at first because those who saw him thought he must be cursed in some fashion, and later because the land he ruled and his castle actually were cursed.

It was stated that his kingdom was once green and good, but the minute he stepped there, the plant life withered and died.

Thus began the reign of King Haggard.

Haggard had no army, and at the time but one servant, but managed to establish himself firmly as ruler of a kingdom. He hired a witch to build his castle, but refused to pay her upon completion. The witch cursed Haggard's castle and the nearby town of Hagsgate, saying the town would only prosper as long as Haggard did, and one of their own would cause the castle to fall. Upon gaining this curse, Haggard immediately moved in.

Haggard had one major personality characteristic, and that was a seemingly perpetual unhappiness. It was stated he would try many things to see if they would make him happy, but while they could divert him for a time, the interest he held in them was soon lost. He attempted to have a typical royal court, tried being a tyrannical dictator, and even went through a phase as a generous ruler... none of which lasted.

Only one thing ever made Haggard truly happy, according to the king himself...

In an area to the north, within Henosis, there dwelt a kingdom of Re'em.

Re'em were considered the most beautiful of all equines, even outshining alicorns- tall, pale unicorns with an ethereal, otherworldly grace.

I like to watch them. They fill me with joy. I am sure it is joy. The first time i felt it, I thought i was going to die. There were two of them in the early morning shadows. One was drinking from a stream, the other was resting her head on his back. I thought I was going to die.

Haggard sought to possess the Re'em. Not their kingdom, but the equines themselves, and so he sent his servant out to collect them.

Many Re'em texts (written by Re'em seers on other continents who witnessed the carnage via farsight) describe the coming of Haggard's minion, a mighty Thag only known as "the Red Bull" or "the Great Red Beast".

The Red Bull gathered all the Re'em in the kingdom for Haggard, magic sealing them in the waves by the castle, so Haggard could watch them and feel complete.

Haggard died long ago, and the town of Hagsgate burned not long after, but the castle still stands, the curse not lifted and now unable to be lifted, the Lost Kingdom of the Re'em remains lost...

...and occasionally, it seems as though something stirs in the caves below the castle, waiting for something to happen...

Speaking of references, here's a neat essay/article by a neat guy about the thing this is referencing.

6208684 Meh, it's okay. He's not covering all the parts, he guesses some, and misinterprets some things:

-Schmendrick wasn't Mommy Fortuna's apprentice, just a wizard she hired

-we never saw the true form of the dragon in the movie- in the book it was a crocodile

-Schmendrick tries 3 times to free the unicorn, not 7

-it's less that he's a crappy wizard and more like he's more of a conduit for magic than someone who can control it

-the cat doesn't refuse to just tell her, he says "I'd tell you if I could, ma'am, but I be a cat, and no cat anywhere ever gave anyone a straight answer."

-Amalthea no longer exists after she's transformed back into the unicorn. The unicorn and Amalthea are two separate people by that point of the story, so Amalthea is effectively dead now.