The article is written on the materials of the report “Before the interregnum: Grand Prince Nikolai Pavlovich and Alexander I in 1825”, at the International conference “Historical memory of Russia and the Decembrists” (14.12.2015, St. Petersburg). The article analyzes the relationship between Alexander I and Grand Prince Nicholas Pavlovich (Nicholas I) in the last years of the Emperor in 1819-1825. The source base of the article is “Notebooks” of Nicholas (1822-1825), memoirs of contemporaries and another unpublished archival sources - chamber-fourrier journals from the funds of Russian state historical archive (RGIA). The author makes conclusion about contacts of the brothers. He considers that their contacts were frequent in this period. They observed family etiquette at least outwardly. Besides the author established the exact date of the first conversation of Alexander I with Nikolai Pavlovich about the succession to the throne, which took place in the Krasnoselsky camps in the 3 of July in 1819. The arti