 In 1843, he completed the three-volume "Asie Centrale", which he dedicated to Czar Nicholas, which he called "an unavoidable step, as the expedition was accomplished at his expense".As of 2016, these works have not been translated to English.His 1829 expedition to Russia when he was an old man is much less known than his five-year travels in Spanish America, which had resulted in many published volumes over the decades since his 1804 return.