The emblem of the Knights of the Round Table worn round the necks of all the Knights was given to them by King Arthur as part of the ceremony of their being made a knight.
The Order's dominant idea was the love of God, men, and noble deeds. The cross in the emblem was to remind them that they were to live pure and stainless lives, to stive after perfection and thus attain the Holy Grail.
The Red Dragon of King Arthur represented their allegiance to the King. The Round Table was illustrative of the Eternity of God, the equality, unity, and comradeship of the Order, and singleness of purpose of all the Knights.