Born in Iasi, he belonged to the Kogalniceanu family of Moldavian boyars, being the son of Vornic Ilie Kogalniceanu, and the great-grandson of Constantin Kogalniceanu (noted for having signed his name to a 1749 document issued by Prince Constantine Mavrocordatos, through which serfdom was disestablished in Moldavia). Mihail's mother, Catinca nee Stavilla (or Stavilla), was, according to Kogalniceanu's own words, "[from] a Romanian family in Bessarabia". The author took pride in noting that "my family has never searched its origins in foreign countries or peoples". Nevertheless, in a speech he gave shortly before his death, Kogalniceanu commented that Catinca Stavilla had been the descendant of "a Genoese family, settled for centuries in the Genoese colony of Cetatea Alba (Akerman), whence it then scattered throughout Bessarabia".  During Milhail Kogalniceanu's lifetime, there was confusion regarding his exact birth year, with several sources erroneously indicating it as 1806; in his speech to the Romanian Academy, he acknowledged this, and gave his exact birth date as present in a register kept by his father. It was also then that he mentioned his godmother was Marghioala Calimach, a Callimachi boyaress who married into the Sturdza family, and was the mother of Mihail Sturdza (Kogalniceanu's would-be protector and foe).  Kogalniceanu was educated at Trei Ierarhi monastery in Iasi, before being tutored by Gherman Vida, a monk who belonged to the Transylvanian School, and who was an associate of Gheorghe Sincai. He completed his primary education in Miroslava, where he attended the Cuenim boarding school. It was during this early period that he first met the poet Vasile Alecsandri (they studied under both Vida and Cuenim), Costache Negri and Cuza. At the time, Kogalniceanu became a passionate student of history, beginning his investigations into old Moldavian chronicles.  With support from Prince Sturdza, Kogalniceanu continued his studies abroad, originally in the French city of Luneville (where he was cared for by Sturdza's former tutor, the abbe Lhomme), and later at the University of Berlin. Among his colleagues was the future philosopher Grigore Sturdza, son of the Moldavian monarch. His stay in Luneville was cut short by the intervention of Russian officials, who were supervising Moldavia under the provisions of the Regulamentul Organic regime, and who believed that, through the influence of Lhomme (a participant in the French Revolution), students were being infused with rebellious ideas; all Moldavian students, including Sturdza's sons and other noblemen, were withdrawn from the school in late 1835, and reassigned to Prussian education institutions.

Answer this question "what did he study?" by extracting the answer from the text above.
Kogalniceanu became a passionate student of history, beginning his investigations into old Moldavian chronicles.