Frühling is also a project that decisively sheds light on the figure of Andrés Isasi (1890-1940), one of the most singular and underrepresented composers of early 20th-century Spain. At the heart of the album, Goikoetxea and Fernández Aguirre offer the world-premiere recording of the complete Lieder-Album op. 16, a cycle composed in Berlin in 1913 and virtually unknown until today. These fourteen songs reveal a cosmopolitan Isasi at a moment of full creative maturity, shaped by his Central European training with Engelbert Humperdinck and attuned to the late-Romantic and Jugendstil currents of his time. The cycle blends intimate lyricism, legendary evocations, decadent impulses, and a refined harmonic language of striking modernity. Works such as Ali Bey, Frühling, Die ungetreue Luise, or Vergiftet sind meine Lieder display a uniquely personal voice that bridges the German Lied tradition with Basque imagery and an advanced European sensibility that was unusual for it's time. Goikoetxea and Fernández Aguirre stand out for their elegance, their textual insight, and their ability to convey the emotional universe-at times naïve, at times shadowed, always intensely poetic-of a composer whose vocal output was long overdue for a first-rate artistic rediscovery. The programme is framed within a broader exploration of Heinrich Heine's profound impact on European music. The album is completed with lieder by Liszt, Grieg, Ives, Rubinstein, Boulanger, Backer-Grøndahl, MacDowell, Sgambatti, and Castelnuovo-Tedesco, composers who, like Isasi, were captivated by the emotional depth and symbolic power of the German poet.