The term "transitional interior design" is relatively new, having only been coined in the last few decades. However, the concept itself is quite old, and can be traced back to the early days of interior design.
Historically, most homes were designed using a more traditional style. This usually involved heavy furnishings, ornate details, and dark colors. However, in the late 18th century, a new style began to emerge. This style was lighter and airier, with more simple furnishings and neutral colors.
This new style quickly gained popularity, particularly among the upper class. As more and more people began to adopt it, transitional interior design slowly started to evolve.