The Serpent Crown was covered in material to reduce its power changing its appearance. It first appeared as the Helmet of Power in the one-shot book Iron Man and Sub-Mariner vol 1 #1 (April, 1968). Its true appearance was revealed in Sub-Mariner vol 1 #9 (January, 1969).
The Serpent Crown is a powerful mystical and very dangerous object which is worn upon the head. It confers the ability to read and control minds (anyone within the sound of the voice of the one wearing the crown), superhuman strength, the power to levitate and telekinetically move others and objects, it bestows the ability to create elaborate illusions, and the crown can project massively destructive bolts of mystical energy and even the ability to manipulate energy and matter.
The crown was created by a race of Serpent Men (who had been created by Set himself millennia before) allied with Lemurian scientists under the direction of the Serpent God, to allow them a conduit to their god.
However, when the Serpent Men were about to access the power of the Crown the Great Cataclysm occurred. This event wrought disasters all over the world, sink both Atlantis and Lemuria and killing most of the remaining Serpent Men. The Crown itself would be lost for centuries.
Finally unearthed by a new race of Lemurians (Homo mermanus), their Emperor, Naga donned the Crown and immediately fell under the control of the Serpent God. Naga wore the Crown for years, rarely taking it off and used its powers in the name of Set. Over time exposure to the Crown altered his appearance, his skin went from a pale blue to a scaly green; also over the years the Crown’s influence was also felt by the general populous altering them similarly.
Eventually, the Crown was stolen from Naga as he slept by a rebel named Pyscatos. He and his allies fled to Antarctica where they began a civilization known as the “Ancients”, they are able to develop telepathy and other similar mental powers through the careful use of the Serpent Crown, but manage to stave off control by encasing the Crown in an unknown substance changing its appearance. These safety measures would prove to not be enough as finally Pyscatos fell under the control of Set and he caused a landslide which ended the ‘Ancient’ civilization. Again, the Serpent Crown was buried and lost, where it remained until the 20th century.
In 1920 Captain Leonard Mckenzie led an expedition to Antarctica where one of the members of the party, Paul Destine, discovered an odd helmet. Donning the “Helmet of Power”, Destine found that his latent psionic powers were awakened and greatly increased and his strength is greatly augmented as well. Thought lost by the rest of the expedition he is left there, but he survives by use of the remaining ‘Ancient’ technology to put himself in suspended animation. Emerging decades later, Destine found his powers further increased from his time in suspended animation.
Calling himself Destiny, he returned to the American continent just after World War II and made a bid at world domination, but was opposed by the son of Captain Mckenzie himself, Namor. After Destiny swiftly defeated Namor and left him an amnesiac for decades.
Eventually Namor arose again to battle Destiny, and during their battle Destiny’s mind snapped he attempted to use his power without the Helmet and fell to his death when he thought he could levitate. Namor took the Helmet and returned with it to Atlantis.
There the Serpent Crown begins to overcome its protective casing and mentally takes Namor’s consort, Lady Dorma, under its control and through her the rest of the Kingdom. Namor then dons the Helmet himself and through force of will frees the Atlanteans. Karthon the Quester eventually recovered the Crown along with Namor as a prisoner and returned to Lemuria. Naga quickly wore the Crown upon Karthon's return and Namor stood defiant against Naga.
Namor and Naga soon engaged each other in battle while Karthon, observing Namor's nobility and Naga's sadism, was having regrets about serving Naga. Namor was about to be swallowed up by a pit created by Naga when Karthon drew his sword and killed Naga.
Namor and Karthon left the Crown on Naga and the creation of the pit caused earthquakes that swallowed Naga and the Crown beneath the ocean floor.
The Crown is recovered by Warlord Krang who delivers it to the superhuman criminal, Viper who in turn kidnaps the President of Roxxon Oil and places the Serpent Crown upon his head. He immediately falls under the influence of Set. Captain America intervenes and the Serpent Crown in lost in a sewer.
The Avengers travel to the Squadron Supreme’s dimension (Earth 712), where they free that Earth from the control of the Serpent Crown, unfortunately falling under its influence only briefly. They return to Earth 616 with that universe’s Serpent Crown but drop it in the Pacific Ocean during a battle with the Living Laser.
Hugh Jones under the control of this universe’s Serpent Crown detects and finds the Serpent Crown from Earth-712 and mystically merges the two to create a Serpent Crown twice as powerful as the original.
He then mentally takes over the population of Washington D.C., but Jones comes into conflict with a group of heroes including the Thing and Scarlet Witch. Scarlet Witch engages the Serpent God on the astral plane, distracting it, as Thing manages to get close enough to Jones to remove the Crown from his head.
The Serpent Crown is brought to Project: PEGASUS for study. Set exerts its influence yet again taking over the entire facility, including the then head-of-security, Quasar. The staff begins working to transport serpent Crowns from all the other dimensions to merge them with the original from Earth-616. They amass 770 such Crowns and merge them into one giant Crown in which to summon the Serpent God, but before they can finish the spell Dr. Strange, Spider-man, Thing, and Scarlet Witch intervene and use the Cosmic Cube to destroy the giant Serpent Crown. Dr. Strange then casts an exorcising spell to remove Set from this plane forever. But with the loss of many of his talismans the spell eventually weakens.
The Deviant priest Ghaur uses this opportunity to create another giant Serpent Crown in which to summon Set to this plane and is briefly successful, but Set is fought back into Limbo by Thor, Thing, Dr. Strange, and Quasar, and is apparently destroyed by Demogorge. The Crown itself was lost in an underground pit where it remains to this day. The event is popularly referred to as Atlantis Attacks.
In Mystic Arcana, it was revealed that the Serpent Crown is one of the four cornerstones of creation. Ian McNee located and retrieved (through many trials and difficulties) all of the four artifacts. The Serpent Crown was in the possession of Nagala at the bottom of the ocean. In Secret Avengers, Beast revealed that there are more than one Serpent Crowns. Roxxon tried to transport one, but the Secret Avengers surgically intercepted and recovered the artifact for Beast's analysis. Then Nova discovered one in space, and was so enthralled by its power he took off his Worldmind Helmet and began to wear this Serpent Crown.