Here are the other sentences I changed into indirect speech.

1)Arthur said that that was where Christ’s blood had been kept after he had been crucified. Two knights soon declared the wanted to look for the Grail for one year and one day.
2)In 537 Arthur had to go to distant land to fight. He asked a knight named Mordred to rule his land until he returned because he knew he was a loyal man. Howver, Mordred told everyone that Arthur was killed in the war, in France.
3) When King Arthur hear the news he got furious and fought a long battle against Mordred.
4) Though King Arthur managed to kill Mordred with his spear, he was mortally wounded by Mordred’s sword which went through Arthur’s helmet and his head. 5) When Arthur was on the point of dying, he called Sir Bedivere and ordered him to give his sword Excalibur back to the Lady of the Lake.
6) As requested, Sir Bedivere went to the lake and threw the sword far into the water.

Straighten out all those pronouns -- make sure the antecedent for every single one is crystal clear.

Check all spelling.

Then repost.

1) Arthur said, "This is where Christ's blood was kept after he was crucified." Two knights then declared that they wanted to search for the Grail for one year and one day.

To change this sentence into indirect speech, you need to report what Arthur said without using direct quotations. Start by introducing that Arthur made a statement or mentioned something. In this case, you can say, "Arthur said that..." Then, rephrase his words, keeping the tense consistent. For example, "This is where Christ's blood was kept after he was crucified," can be changed to "that was where Christ's blood had been kept after he had been crucified."

2) In 537, Arthur had to go to a distant land to fight. He asked a knight named Mordred to rule his land until he returned because he knew he was a loyal man. However, Mordred told everyone that Arthur was killed in the war, in France.

To convert this into indirect speech, you need to report what Arthur asked and what Mordred said. Start by saying, "Arthur asked..." and restate his request. For example, "Arthur asked Mordred to rule his land until he returned." Then, introduce Mordred's words by saying, "However, Mordred informed everyone that..." and rephrase what he said. For instance, "Mordred told everyone that Arthur had been killed in the war, in France."

3) When King Arthur heard the news, he got furious and fought a long battle against Mordred.

To change this sentence into indirect speech, you need to report what King Arthur did after hearing the news. Start by saying, "When King Arthur heard the news..." and then rephrase what he did. For example, "When King Arthur heard the news, he became furious and engaged in a long battle against Mordred."

4) Although King Arthur managed to kill Mordred with his spear, he was mortally wounded by Mordred's sword, which went through Arthur's helmet and his head.

To convert this into indirect speech, you need to report the events. Start by saying, "Although King Arthur managed to kill Mordred with his spear..." and describe the outcome. For example, "Although King Arthur managed to kill Mordred with his spear, he ended up being mortally wounded by Mordred's sword, which penetrated through Arthur's helmet and his head."

5) When Arthur was on the point of dying, he called Sir Bedivere and ordered him to give his sword Excalibur back to the Lady of the Lake.

To change this into indirect speech, you need to report what Arthur did and said. Start by saying, "When Arthur was on the point of dying..." and rephrase what he did. For example, "When Arthur was close to death, he summoned Sir Bedivere and instructed him to return his sword Excalibur to the Lady of the Lake."

6) As requested, Sir Bedivere went to the lake and threw the sword far into the water.

This sentence is already in indirect speech, so no changes are necessary.