I will simply say what I know in my own words.
Merlin is a close friend of King Arthur, a great magician in history. Legend has it that Merlin led King Arthur to the legend of the king (the sword in the lake) and ruled England. Is a legend. It is not known whether it is true or not. It is said that Merlin is the son of a nun named Carmelius and an elf. He predicted that Arthur would give birth to Uther Pendragon. After Uther Pendragon's death, he became Arthur's most trusted adviser, predicted Arthur and used magic to help him.
Then King Arthur. King Arthur is the legendary king of England, the leader of the knights of the Round Table, and also a legend close to myth. After the collapse of the Roman Empire, he led the Knights of the Round Table to unify the British Isles and was honored as King Arthur by later generations.
King Arthur is the illegitimate child of Uther Pendragon. Before that, Uther Pendragon's first wife was a daughter named Morgan (Morgan in Merlin's legend, both names are the same ~). Later, King Arthur had an incest with Morgan and gave birth to Mordred without knowing it. (Later, the baby rebelled and died with King Arthur, but some people said that he didn't die. After Uther Pendragon's death, the domestic situation was turbulent ~ The Bishop listened to Merlin's suggestion, summoned all the noble knights, and elected the new king of Britain with a sword in the stone. Later, it was King Arthur who drew his sword. (See Baidu Encyclopedia for details) Soon after, he married Queen Guinevere as a dowry, and the Queen's father gave King Arthur that famous round table. Later, the sword in the stone was broken in another battle, and the goddess in the lake gave it to Rapier Excalibur of King Arthur. According to legend, the scabbard of this sword is the most valuable, because King Arthur won't bleed or get hurt as long as he wears it, but later it was stolen by Morgana and thrown into the lake. It can also be seen from the preview of the third season of the Legend of Merlin that Morgana did steal the scabbard. )
Then we turned to talk about Queen Guinevere. After world peace, King Arthur began to look for the legendary treasure Holy Grail, and the knights of the Round Table went back one by one, and the kingdom began to decline. At this time, the extramarital affair between Lancelot, King Arthur's first knight, and Queen Guinevere was exposed. Lancelot escaped and Queen Guinevere was burned by King Arthur. However, Lancelot rushed into the execution ground to rescue Guinevere and fled to France to establish his own territory. Although Lancelot reluctantly returned to Guinevere for fear of fame, King Arthur sent troops to France, leaving his cousin Calvin Ying and his nephew Mordred to run the kingdom. Later, after the death of King Arthur, Lancelot returned to England to pursue Guinevere, but she had become a nun, so Lancelot became a Taoist. )
Then there was the rebellion in Mordred. When King Arthur sent his troops on a private expedition, launched a rebellion and forced him to marry Guinevere, he killed Gavin. In the Battle of the Sword Bar, King Arthur killed Mordred with a thin sword, and he himself was seriously injured.
It is said that King Arthur, who was dying, was taken to Avalon by a fairy. It is said that he was finally buried there, and people believe that King Arthur is not dead, and he will come back again to save the world. It is said that this was in 452 AD.
The legend of King Arthur ends here. Merlin fell in love with the witch Vivian after the death of King Arthur (some people say that Vivian is a disciple of Merlin, others say that she is a goddess in the lake), but Vivian seems to hate Merlin, lied to Merlin and vowed not to use magic on herself, and later sealed Merlin in a tree. Merlin also kept his promise not to use magic on himself, so he kept it in his heart.
If you want to know the story of how Merlin helped King Arthur, you have to take your time and search for Merlin with Baidu Encyclopedia. There is one in it. (The fifth one in the catalogue is more specific. 0
I hope my answer can help you. You can also call me Baidu hi if you have any questions.
And the legend of Merlin. Very nice ~