Once Bava had provided the inspiration, other directors in his native Italy were not far behind. Screenwriter Mino Guerrini (who collaborated on the screenplay for The Girl Who Knew Too Much) would soon become a prolific director himself. Films such as The Third Eye (1966) and Murder by Appointment (1966) would see elements of Bava’s gothic horror, flamboyant style and dark mystery infused with a healthy dose of comedic timing. While Guerrini’s films would not quite solidify the genre, they bore many elements of the perfect Giallo recipe. Angelo Dorigo’s trade in Agatha Christie-style mysteries saw him direct A for Assassin (1966) about a warring family gathered together for the reading of a will who are slowly whittled down by an unknown assailant’s dagger. One year later he would return with Killer Without A Face (1967) a noir thriller replete with a former detective turned bodyguard, femme fatale and various seedy locations (such as a meat packing plant).

Before long, Italy had a burgeoning new genre on its hands. The Monster of Venice (1965, dir Dino Tavella) featured a serial killer in scuba gear; Libido (1965, dir Ernesto Gastaldi) features a diabolical plot in the villa of a sex maniac; The Sweet Body of Deborah (1968, dir Romolo Guerrieri) is a tale of murder, suicide, a voyeur and death threats. More and more lurid thrillers were released year on year, often with titillating titles and exploitative content.

The Giallo was born.

It was not until the 1970s that the genre began to truly take off outside of Italy. Ornately-titled productions such as Dario Argento’s The Bird with the Crystal Plumage (1970) and The Cat O Nine Tails (1971), Lucio Fulci’s Lizard in a Woman’s Skin (1971) and Sergio Martino’s The Strange Vice of Mrs Wardh (1971) would further explore the themes, tropes and devices that Bava had established, elevating the exploitative base content into artful, stylish cinema.

ON FRIDAY: We take a look at how Bava returned to Giallo tropes in 1971 and helped set the blueprint for the modern slasher genre.