“Siren Script takes its cue from BB&S’s Stationers Semiscript (metal, 1899) [originally Palmer by Inland] and its countless imitations/inspirations from throughout the 20th century, particularly a variety of uncredited film faces from the 1960s.” — Canada Type

One of the additional sources appears to be Isabel / Hispania (Schelter & Giesecke, 1899).