Also-rans and wannabes would come and go, and some remain today, including the Chevrolet Camaro. But the Ford Mustang is the original pony car—a car that would define an entire segment in the years to come.

The story began with Lee Iacocca, who championed a new kind of personal-luxury car that had defined goals: seating for four with front bucket seats, a floor-mounted shifter, a weight of less than 2,500 pounds, a length no longer than 180 inches, a sale price of less than $2,500, and multiple power and luxury options.

The Mustang became reality with a small batch of cars enthusiasts refer to as “1964 ½” models. All first-year Mustangs received a 1965 VIN when production started in March 1964, but those first ‘Stangs bore notable differences compared to the cars that began rolling off assembly lines in August of 1964.

1965 Ford Mustang bearing VIN 5F07U100002

1965 Ford Mustang bearing VIN 5F07U100002

These 1964 ½ cars had their own engine lineup options, a generator charging system instead of an alternator, and other small quirks. It’s easy to call the first Mustangs the closest thing to a production prototype the automotive industry will ever see.

Unlike true 1965 Mustangs, a 170-cubic-inch inline-6 engine was standard, while 164- horsepower 260, 210-hp 289 4-valve low-compression, and 271-hp 289 cubic-inch Hi-Po V-8s were sold as options. To save on development costs, Iacocca’s team used chassis, suspension, and drivetrain components from the Ford Falcon.

Little did the team know that they had done more than piece together a lighter and leaner Falcon. They created an American icon.

Sales exploded in the first year to tally nearly 700,000 Mustangs sold between the early 1964 ½ and 1965 models. Mustang sales peaked in 1966 around 607,000 cars sold in a single model year. Ford built the car mid-century youngsters desperately craved, a car their parents never clamored for. Yet, all of the first-year success predated a splash that was yet to come. In 1965, Ford brought on Carroll Shelby to introduce the Shelby GT350. In 1967, Ford doubled down and ushered in the GT500. The Mustang got real performance, just in time to take on the Challengers and Chargers and Camaros from across town.

The Ford Mustang can stake a claim not many other cars can: it’s been in continuous production since the first models left the Dearborn factory. Over decades of production, the Mustang has seen its highs and lows, but one thing has remained the same: it’s America’s car, the original pony car, and it always will be.

Note to readers: Motor Authority has compiled 100 cars that have forever changed enthusiasts. From supercars and sedans to SUVs and muscle cars, these are the cars that have sparked our love for cars. Think we’ve missed something? Leave a comment below or contact us here.