From roughly the Restoration era to the Victorian era -- back when the peerage was strong in England, when the social elite were the center of English culture, and the masses could be safely ignored -- the rich and socially verdant would travel to London for the Season1. In the period before motor cars became ubiquitous, spending time outdoors, visiting and promenading, was a major part of the Season. The best time and place to do this was the fashionable hour. That's right, time and place.
When: Primarily between about 4:30 p.m. to about 7:00 p.m.
Where: In and about Hyde Park.
Who: Well, everyone, really, but particularly the upper classes.
Why: To see and be seen.
In London from the late 1600s and on until about 1915 the fashionable hour was a chance for the wealthy to come out and mix and mingle. You could chat with friends, meet a popular actor, dodge a crass young fop on a hackney, and meet your beau on appropriately neutral grounds. And, of course, show off your new clothes, mounts, companions, pets, carriages, and servants.
As with so many Society events, the ins-and-outs of fashionable hours were not simple. The fashionable hour for riders, for example, actually peaked from 8:00 a.m. to noon on Rotten Row2, where no carriages were permitted3; Rotten Row was a place for the younger set to mingle more informally, show off their horses, engage in ad hoc races, and impress each other with their riding abilities. Many of these same riders would reappear in the afternoon, perhaps to mingle with the carriage riders.
For the carriage-riders South Carriage Drive was a popular promenade, and conveniently close to Rotten Row. The afternoon would be filled with landaus, cabriolets, phaetons, and curricles, small, open carriages to allow the upper classes to visit in a most mobile fashion. Ladies tended to save their outings until a bit later in the afternoon, about 5:30, while the youth might take their outings earlier.
While young ladies could be found riding all around, the Lady's Mile along the north bank of the Serpentine was a particularly proper spot for them to pass; and where there are young ladies, young gentlemen are also found. Naturally, coaching clubs comprised of young gentlemen took to meeting along this stretch, including the infamous Four-in-Hand Club.
During the rule of Queen Anne the fashionable hour made a shift to include the growing merchant class, much to the dismay of many of the established families. This gave rise to the Church Parade, a flood of well-dressed and upwardly-mobile church goers every Sunday, lasting throughout the afternoon. These park-goers tended to be pedestrians who would stroll or sit on benches to chat, frequenting the footpaths on either side of Rotten Row. This practice, started in the early 1700s, was maintained continuously into the early 1900s, and while arguably not not a part of the fashionable hour as conceived of by the upper crust, it was certainly part of the gestalt in which the fashionable traveled.
Of course, this tradition lasted 200 years, and passed through numerous changes in social expectations and vehicle design; what I have listed here is a brief mishmash of traditions and informal habit. I have also ignored all the special events that intruded into Hyde Park and thus affected the fashionable hour; ice skating on the Serpentine in the winter, cricket games in the park during warm weather, and somewhat obnoxious parades of the Four-in-Hand Club around the park. In later years Hyde Park was the place for protests by the Chartists and the Great Exhibition of 1851, marking the shift into a more egalitarian society.
Footnotes:
1. The Season was a meta-social event for those who lived and breathed social events. It loosely correlated with the sitting of Parliament, and could begin any time after Christmas, although it REALLY got going around Easter. It would go until The twelfth of August, known as the Glorious Twelfth, which marked the opening of the grouse hunting season, heralding the flood of peerage heading out to their country estates.
2. A pleasant and well-lit boulevard along the south side of Hyde Park, it was built for king William III who needed a kingly route from Kensington Palace to St James's Palace. It was called Route de Roi (French for King's Road), which became 'Rotten Row' when spoken by the crass English masses. Although wide and well-appointed, it was not paved, being covered in gravel or rough sand, as it remains today.
3. The King and the Duke of St Albans were allowed to ride their carriages through Rotten Row, of course. The king can do whatever he wants, and the Duke earned this right as per his post as Hereditary Grand Falconer.