Was it ever released in theatres?

Because I wasn't born when the PEPLUM explosion occurred between 1958 up until 1965 I often wonder if some titles from the hundreds made back then ever made it on the big silver screen. With TV gaining popularity for entertainment in the 1960s several titles, like PERSEUS THE INVINCIBLE or MACISTE VS THE MOLE MEN, never made it to theatres and were sold directly to the US TV market (and eventually fell into the public domain) while other seemingly more obscure titles, like THE SECRET SEVEN, made it to theatres. Personally, I would rather see PERSEUS THE INVINCIBLE on the big screen than a generic action film like THE SECRET SEVEN.

So looking at this page from THE SECRET SEVEN pressbook, this tells me that this specific title is NOT in public domain. MGM distributed it and today TCM owns it (link). Big Hollywood studios back then were late in acquiring trendy titles from Italian or European studios. After the phenomenal success of the two HERCULES films in the late 1950s, made by Pietro Francisci, big studios started looking at the genre as possible source for easy profit. THE GIANT OF MARATHON is a good early example of a seemingly Hollywood-made PEPLUM film but was, in actuality, still pretty much a totally European co-production. MGM distributed MARATHON in North America and eventually released the copyright for it which is why MARATHON is in the public domain in the US/Canada.

Riding on the success of his HERCULES films, Pietro Francisci's last 3 1960s PEPLUM films were co-financed by Hollywood studios: Paramount with SIEGE OF SYRACUSE; Columbia with SAPPHO - VENUS OF LESBOS and MGM with HERCULES, SAMSON & ULYSSES.  This was very rare back then for Hollywood to specifically finance an Italian filmmaker's productions. Heck, even early Sergio Leone or Fellini productions didn't get this treatment. All 3 were released in theatres back then and all 3 are not in the public domain. And only the last title has finally made it to DVD. SIEGE and SAPPHO are in perpetual limbo.

By the time THE SECRET SEVEN was released, in 1964, the genre was all but dead and, looking at the pressbook, it's odd to see such a minor title released by a studio when the genre was on its last legs compared to when the genre was hot and few of the big genre titles were released/financed by any major. Today, THE SECRET SEVEN is all but forgotten, except for some PEPLUM fans out there.  Because it's forgotten (very little outcry for it to be release) and it's NOT in the public domain, the chances of this film becoming available for the home market in North America are very slim, even with the Warner Archive process. But when you think about it, if major studios had been quick in co-financing films early on during the PEPLUM explosion one can only think of how cool it would have been if MACISTE VS THE MOLE MEN had been released by a major studio instead of late comers like THE SECRET SEVEN. Oh well...