The garden to the east of the buildings was part of the original ground, but has had a career and history of its own. It was the famous Ranelagh Gardens, which enchanted the beaux and fair ladies of the eighteenth century. From 1742 to 1803 its glories lasted. Ranelagh House was built by the Earl of that name, who was Paymaster to the Forces in the reign of James II., a clever, unscrupulous person, who amassed considerable wealth in the course of his office-work. He obtained a grant of the land from Chelsea Hospital, built a house and laid out a garden, where the "plots, borders, and walks" were "curiously kept, and elegantly designed." After passing through the hands of his daughter, Lady Catherine Jones, the property was sold to Swift and Timbrell, who leased it to Lacey, the patentee of Drury Lane Theatre. The idea was to turn it into a winter Vauxhall. Eventually it was open from Easter till the end of the summer, and effectually outshone Vauxhall. Walpole, in a letter two days after it was first opened, did not think much of it. "I was there, last night, but did not find the joy of it. Vauxhall is a little better, for the garden is pleasanter, and one goes to it by water." Two years later he wrote in a very different strain. "Every night constantly I go to Ranelagh, which has totally beat Vauxhall. Nobody goes anywhere else-everybody goes there. My Lord Chesterfield is so fond of it, that he says he has ordered all his letters to be directed thither." Fanny Burney, in "Evelina," to bring out the character of the "surly, vulgar, and disagreeable man," makes him abuse the place which fascinated polite society. "There's your famous Ranelagh, that you make such a fuss about; why, what a dull place is that!" The chief amusement was walking about and looking at each other, as the poem by Bloomfield puts it- "We had seen every soul that was in it, Then we went round and saw them again."
The great attraction was the Rotunda, supposed to be like the Pantheon at Rome. The outside diameter was 185 feet. An arcade ran all round, and above it a gallery, with steps up to it through four Doric porticos. Over the gallery were sixty windows, and the whole was surmounted by a slate roof. In the middle, supporting the roof, was a huge fireplace, on the space at first occupied by the orchestra. "Round the Rotunda," inside, were "47 boxes... with a table and cloth spread in each; in these the company" were "regaled, without any further expense, with tea and coffee." The whole was adorned with looking-glasses and paintings, imitation marble, stucco, and gilding. Dr. Arne wrote music for the special performances; breakfasts were at one time the rage, and at another masquerades were the order of the day; while fireworks and illuminations amused the company at intervals, all through the years in which Ranelagh was prosperous. "There thousands of gay lamps aspir'd To the tops of the trees and beyond; And, what was most hugely admired, They looked upside-down in a pond. The blaze scarce an eagle could bear And an owl had most surely been slain; We returned to the circle, and then- And then we went round it again."
One of the last entertainments at Ranelagh was the Installation Ball of the Knights of the Bath in 1803; and a few years afterwards all trace of Ranelagh House, the Rotunda, and even the Garden was gone. The ground reverted to Chelsea Hospital, and not a vestige of the former glories is left. The pleasant shady walks and undulating lawns on the site, bear no resemblance to the lines of the former gardens, and only some of the older trees can have been there when Lord Chesterfield and Walpole were paying it daily visits.