What critical development transformed the button from a mere decoration into an essential component of garment construction?

Answer

The advent of a reliably sewn, reinforced buttonhole

The utility of the button as a true fastener was severely constrained until the buttonhole was developed. A buttonhole is defined as a deliberately reinforced slit sewn into the fabric specifically to accommodate the button shank passing through it. This standardization and reinforcement, which gained widespread adoption particularly in Europe during the Middle Ages, made possible the construction of more closely fitted and structured clothing, elevating the button to a necessary piece of hardware rather than just an adornment.

What critical development transformed the button from a mere decoration into an essential component of garment construction?
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