Josh,

I can't add anything to what you've already discovered - indeed you've gone beyond what I knew with the name of the previous owner of the house.

As you probably already know, there are some good private letters from Wellington describing his time in Russia, written to Mrs Arbuthnot, and published in Wellington and His Friends (p 56-64). However these are only extracts, and it is possible that there is a passage about the house in which he was staying in the originals, which are held by the current Duke of Wellington at Stratfield Saye. It is possible that if you wrote to the Archivist there they might be able to answer the query, as it would simply involve looking at a handful of specific letters.

There are also letters home from Fitzroy Somerset, who accompanied Wellington. John Sweetman quotes briefly from one of these in his biography (Raglan. From the Peninsula to the Crimea p 79 where Sweetman writes that 'The Duke and his suite, including Lord Fitzroy, were lodged in a house provided by the Emperor and allocated carriages and horses to ride.') Again there may be more detail in the unpublished papers, which I believe are now held by the Gwent Record Office. (And again it is worth trying an email enquiry before you either give up or decide that there is no alternative but a personal visit).

It is possible, though not very likely, that the information you are looking for is included in the expenses for Wellington's mission, which would probably have been included in some Parliamentary Papers, but that might take quite a bit of finding with a low probability of success.

An easier, but also unlikely, avenue would be a biography of Lord Strangford who was, I think, the British ambassador to Russia at the time and in St Petersburg.

But this may all be looking at the question from the wrong end. You already know the house in which Wellington stayed; so the question is really where was that house? It is possible that you could find that in a contemporary map or guide to St Petersburg - although that might be a bit optimistic. Houses were numbered in London in the early nineteenth century, but I don't know if they were in other cities in Europe - St Petersburg would probably have been quite consciously modern and likely to adopt such usages.

Anyway, good luck with the hunt - it is always interesting to see just how much information you can squeeze out of the sources, and where you run into a brick wall.

Rory