Shakhmatov and Karskiy. Tarashkyevich had completed the work by the autumn of 1917, even moving from the tumultuous Petrograd of 1917 to the relative calm of Finland in order to be able to complete it uninterrupted. By the summer of 1918, it became obvious that there were insurmountable problems with the printing of Tarashkyevich's grammar in Petrograd: a lack of paper, type and qualified personnel. Meanwhile, his grammar had apparently been planned to be adopted in the workers' and peasants' schools of Belarus that were to be set up, so Tarashkyevich was permitted to print his book abroad. In June 1918, he arrived in Vilnius, via Finland. The Belarusian Committee petitioned the administration to allow the book to be printed. Finally, the first edition of the "Belarusian grammar for schools" was printed (Vil'nya, 1918). There existed at least two other contemporary attempts at codifying the Belarusian grammar. In 1915, Rev. Balyaslaw Pachopka had prepared a Belarusian grammar using the Latin script. Belarusian linguist S. M. Nyekrashevich considered Pachopka's grammar unscientific and ignorant of the principles of the language. But Pachopka's grammar was reportedly taught in an unidentified number of schools, from 1918 for an unspecified period. Another grammar was supposedly jointly prepared by A. Lutskyevich and Ya. Stankyevich, and differed from Tarashkyevich's grammar somewhat in the resolution of some key aspects. 1914–1917 On 22 December 1915, Paul von Hindenburg issued an order on schooling in German Army-occupied territories in the Russian Empire (Ober Ost), banning schooling in Russian and including the Belarusian language in an exclusive list of four languages made mandatory in the respective native schooling systems (Belarusian, Lithuanian, Polish, Yiddish). School attendance was not made mandatory, though. Passports at this time were bilingual, in German and in one of the "native languages". Also at this time, Belarusian preparatory schools, printing houses, press organs were opened (see also: Homan (1916)). 1917–1920 After the 1917 February Revolution in Russia, the Belarusian language became an important factor in political activities in the Belarusian lands (see also: Central Council of Belarusian Organisations, Great Belarusian Council, First All-Belarusian Congress, Belnatskom). In the Belarusian People's Republic, Belarusian was used as the only official language (decreed by Belarusian People's Secretariat on 28 April 1918). Subsequently, in the Belarusian SSR, Belarusian was decreed to be one of the four (Belarusian, Polish, Russian, and Yiddish) official languages (decreed by Central Executive Committee of BSSR in February 1921).