Over in /r/artefactporn this image was posted. There were the obvious penis jokes, but it less to a discussion about whether the form of the helmet is purposely phallic, or if it was simply a product of giving the helmet the surfaces and curves that would give the greatest ability to deflect blows to the side.
I believe, based on my understanding of the cultural mores of the time (how un-tabboo and unsexualized male nudity was and how phalluses were a symbol of virility and strength), that this is no coincidence. Others have said it's simply a the best shape for protection.
Is there any thoughts or consensus on the matter?
The object is a typical fully developed Corinthian helmet. These helmets were the product of a steady development from the 8th century BC onwards from more poorly fitted and top-heavy Assyrian-inspired helmet types to a form of head protection that fully enclosed the skull, fitted comfortably around the head, and covered as much as possible. They were made out of a single sheet of hammered bronze. They would typically have been worn with a crest made of horse hair; with crest attached, the helmet looks considerably less phallic. The peak of the face plate simply converges on the root of the crest, rather than creating the semblance of the base of a glans.
It is theoretically possible that the design was intended to resemble the head of an erect penis. We don't have any source that confirms or denies this outright. However, it seems very unlikely when we consider that statues and paintings representing the Greek male ideal invariably feature a small, flaccid member. Big dicks were regarded as a sign of poor self-control, and belonged in depictions of low-born men, barbarians and satyrs. Since no self-respecting Greek citizen of means would have himself depicted with a massive pecker, it's hard to believe that he would have dressed up as one when going into battle. Moreover, vase paintings give us hundreds of examples of different shield blazons, but I know of none showing a phallus, despite the widespread use and positive associations of the symbol.
The fully developed Corinthian helmet went out of style around the time the one found at Denda was made. Later helmets of the Attic or Boiotian type or the simple pilos helmet did not have the features we might see as phallic. It seems the particular shape of the Corinthian helmet was not something the Greeks created intentionally for its possible symbolism.
In addition to /u/Iphikrates's good answer, I'd like to point out that the helmet more closely resembles a circumcised penis than an uncircumcised one. (You can Google that one yourself.) Since Greeks did not practice circumcision, this is a reason to doubt that it is intentionally shaped like a penis.
