The Russian Orthodox Church forbids marriage between certain degrees of kinship, as do most religions. In the Orthodox faith this extends to forbid a sister from marrying her brother's wife's brother, or a brother from marrying his sister's husband's sister. Therefore Marya can only marry Nikolai if Prince Andrei and Natasha do not get married.
Count Nikolai Kamensky (1776-1811) was a Russian general, the son of Field-Marshall Mikhail Kamensky, who was killed by one of his serfs in retribution for his cruel treatment of them. Nikolai Kamensky appeared to be equally ruthless about the lives of the soldiers fighting under him, and achieved many of his greatest victories at the cost of many lives. He fought in the Russo-Turkish war of 1806-12, where he stormed Silistra and Pazardzhik before succumbing to a fever. He died in Odessa in 1811, before the end of the war. The British actor Helen Mirren is a descendant of the Kamensky family: she is Nikolai Kamensky's great-great-great-granddaughter.
The broadsheet, or broadside, was a one-page newspaper issued to announce a proclamation, or a single event. They would be pasted up like posters in public places to inform the populace of important events and edicts.