Belgrave Square is one of the grandest 19th century squares in London. It is a centrepiece of Belgravia, and was laid out by the property contractor Thomas Cubitt for the the 2nd Earl Grosvenor in the 1820s. Most of the houses were occupied by 1840.

The square consists of four terraces, each made up of eleven very grand white stuccoed houses; detached mansions in three of the corners; and a private central garden. The terraces were designed by George Basevi and are possibly the grandest houses ever built in London on a speculative basis. The largest of the corner mansions, Seaford House in the south east corner, was designed by Philip Hardwick, and the one in the north west corner was designed by Sir Robert Smirke.

From its construction until World War II the square was occupied by leading members of the British aristocracy, with an increasing number of plutocrats mixed in in later decades. It is also, and remains to this day, the home of a number of embassies, including the German Embassy, which occupies three houses on the west side. After World War II most of the houses were converted into offices for charities and institutes. This is now being reversed, with leases of three houses being offered for sale and conversion to residential use by the Grosvenor Estate in 2004. The present Duke of Westminster remains the freeholder of the square.

Source

Georgian London, by John Summerson. 1988 edition. ISBN 0-7126-2095-8