As a Romance language, Romanian continued to be written in Latin script until the Council of Florence in 1439. Increasingly influenced by Russia as the Greek Byzantine Empire declined and was gradually conquered by the Ottoman Empire in the 15th century, the Eastern Orthodox Church had begun promoting the Slavic Cyrillic. In the 19th century, the Romanians returned to the Latin alphabet under the influence of nationalism. The linguist Ion Heliade Rădulescu first proposed a simplified version of Cyrillic in 1829, but in 1838, he introduced a mixed alphabet containing 19 Cyrillic and 10 Latin letters, and an [i] and [o] that could be both. This 'transitional orthography' was widely used until the official adoption of a completely Latin Romanian alphabet in Wallachia (1860) and Moldavia (1863), that were gradually united since 1859 to become the Kingdom of Romania in 1881. Romanian intellectuals in Transylvania, then still part of Austria-Hungary, and scholars in Wallachia-Moldavia agreed to cleanse the language from all non-Latin elements (Greek, Magyar, Slavic, and Ottoman), and to emulate French wherever needed.