It was a sign of obeisance to members of the Landsraad that they were invited by Muad'Dib to the Imperium's capital, Arrakis, to show loyalty to Paul's Jihad. Princess Irulan, wife of the Emperor, sent out the invitations to each and every noble of the Known Universe. Each House was expected to send a representative to the ceremony, and to bring a cargo hold of water, which the Emperor distributed to the peasants of Arrakeen.
The Great Surrender ceremony itself coincided with the completion of Phase I of the Imperial Palace that was being built by the Emperor, and his Chief Construction Engineer, the Swordmaster Whitmore Bludd. The ceremony was held in the fantastic Celestial Audience Chamber, which contained frescoes on its' ceiling, depicting great moments in the life of Paul, and his father, Duke Leto Atreides I.
Security was high at the event, and personal shields were forbidden by Korba, the leader of Fremen security; in case an assassin brought a lasgun to the event. Almost all of the nobility of the Landsraad sent representatives or personally went themselves to the event. House Corrino, sent the deposed Emperor Shaddam Corrino IV's daughter, Rugi Corrino, as its' standard-bearer.
As the event began, well-hidden traps began to sprang in the Chamber, and filled the gathering hall with paralytic gas. Poison darts sprang forth out of the walls, and impaled themselves into some of the gathered nobles, who were sitting in the giant audience room. Then, deadly hunter-seekers emitted themselves from the ceiling and walls, in an attempt to kill the Emperor Paul himself. As Paul was stung by one hunter-seeker, he was able to adjust his body chemistry to neutralize the poison as the next stung him with a different type of toxin.
Paul quickly defeated all of the seekers, and batted down all of the darts with his knife, as Stilgar and Korba tried to restore order. Swordmaster Bludd, amazed at the agility of Paul, was shocked that the Emperor was so able to defeat the seekers without his aid, and that Paul did not need his protection.
After another short time of perhaps minutes, a large bomb went off beneath Muad'Dib's throne, which threw broken bits of wood and debris through the Chamber. Sadness was realized as Irulan screamed that her sister, Rugi Corrino, had been killed as order was restored.
As all involved were questioned it became apparent that the individual who had placed all of the darts and hunter-seekers must have had an extensive knowledge of the Palace itself. Individuals were interrogated one by one, and blame eventually came to be placed upon House Atreides' old friend, Bludd himself. The Swordmaster explained that years earlier, he had failed House Ecaz at the beginning of the War of Assassins of 10,187 AG with House Moritani, and had let Ilesa Ecaz perish because of his hesitation.
Bludd admitted that he had concocted the twisted killing attempt as soon as work began on the Palace as he had wanted to save Paul's life in front of a great multitude to atone for what he considered his great sin from years before. Paul sentenced the insane Swordmaster Bludd to death, and allowed his Fremen fanatics to personally rip Bludd apart in the Palace Courtyard.
To further his reputation among Landsraad rebels, Memnon Thorvald claimed that he had arranged the assassination attempt to gather more followers.