A member of one of Russia's Rurikid families, Pyotr Borisovich Kozlovsky had a short career as a diplomat, was a writer and translator, but is known mainly for his contacts with the numerous literary figures with whom he became acquainted during his extensive and protracted travels in Western Europe.

His early intellectual development was greatly aided by contact with the cultivated foreigners, primarily French emigrants, who were frequent visitors to his parental home.

During the brief peace between France and Russia after the signing of the Treaties of Tilsit in 1807, Kozlovsky helped a group of French officers escape English captivity, for which he was awarded the Cross of the Légion d'honneur by the Emperor Napoleon Bonaparte.

He was closely involved in the negotiations on the demarcation of the frontiers between Switzerland, France, and the Kingdom of Sardinia and was also a minor member of the Russian delegation to the Congress of Vienna (1814–1815).

During this period he turns up for varying lengths of time in Austria (1821–1822, in Vienna, Graz, Prague, Teplitz), Switzerland, France (1823–1824 in Paris), Germany (1825-6, in Berlin), the Netherlands and London (from 1829).

Sophie was in close contact with the French novelist Honoré de Balzac, who followed Kozlovsky as the lover of Frances Sarah Lovell (1804–1883), wife of Count Emilio Guidoboni-Visconti.

One sister, Maria Borisovna (1788–1851), a poet in her own right, was the mother of the composer Alexander Sergeyevich Dargomyzhsky (Александр Сергеевич Даргомыжский), another, Daria Borisovna, was married to the poet, translator and state councillor Michail Sergeyevich Kaisarov (1780–1825, Михаил Сергеевич Кайсаров) Even before his exile Kozlovsky had become a well-known figure in polite society and literary circles in Western Europe.

Galt dedicated his Letters from the Levant to him and also provided him with introductions to Byron and Sir Walter Scott when Kozlovsky passed through London on his way to Turin.

A fat nephew of the Princess Galitzin, a Prince something, Koslouski I believe, was going to Sardinia, but he has fallen so desperately in love with a beautiful girl, Mrs Tom Sheridan's youngest sister, that he scarcely can ...".