DISCLAIMER: I do not own the rights to Harry Potter etc. I'm sure you can fill in the rest.
In Wizarding Society purebloods were accustomed to getting whatever they wanted, from the latest broom to a new manor house complete with house elves. However historically wealthy pureblood heirs had a problem in successfully wooing the perfect spouse; mostly of course because they had been spoilt and pampered for their entire lives and as such normal wholesome people wanted very little to do with them. Consequently, purebloods being purebloods passed a new international law – the Ribbon law – as it became commonly known. This law stated that any pureblood heir of a certain rank, once they were of age, could sent off a letter of courting bound with a red ribbon, and the recipient could not refuse the proposal. Of course some safeguards were put in place to protect future spouses, but these were few and far between.
Over time the Great pureblood families died out until only 8 were left throughout Europe and as the Great pureblood families were the only ones with sufficient rank to send a Ribbon proposal, these too faded into obscurity, that is until October 1995 when once again a Ribbon proposal appeared sending shock waves throughout the Wizarding world.