I actually wrote a thesis on this subject not too long ago but I will give a refresher. The Gilded Age started during the Reconstruction period as the Robber Barrons and their fortunes came to fruition after the Civil War.By the 1890s the period was full swing.However the Gilded Age was more than a time period, it was a lifestyle. Lavish , decadent and corrupt at the same time. It was all about yachts, millionares outspending each other and showing off, being at certain places during the year, winters in Europe, summers in Newport etc. It was about lavish parties costing hundreds of thousands(BACK THEN), and going on till daybreak. One party giver even had nightengales singing in transplanted rose trees at his soiree. Women changing clothes 7-8 times a day as well as living by a massive set of social rules and etiquettes that dominated every aspect of life. You have to read some books on this to see how these people lived, very fascinating and more detailed than what I mentioned. Of course the Income Tax of 1913 put a damper on this lifestyle, and the War pretty much finished it. Even though some people in the new post war era tried to live like everything was the same, by the 20s this world was a memory.