Celestion.
The Celestion Blue came first — an alnico twelve that went into the Vox AC30 and stayed there. Its chimed, three-dimensional top runs through everything from the Beatles to The Edge. The G12M Greenback arrived in 1968, a ceramic twelve with a round, woody midrange and a cooperative break-up under drive that became the Marshall sound through the seventies, and by extension most of what British rock sounded like for the decade after.
The Vintage 30 followed in 1986 — a harder-hitting ceramic with a pronounced 2.5 kHz presence peak that cut through high-gain mixes the way the Greenback never had to. It’s the default British high-gain driver today, and many modern 4×12s ship with one or a licensed clone. Celestion’s parallel alnico line — the Gold, Ruby, and Cream — extends the Blue’s voice into higher power ratings.