Transylvania, Banat, and Bukovina, where the largest German-speaking groups once lived alongside the Romanian ethnic majority. Furthermore, the bilateral political and cultural relationships between post–1989 Romania and the unified Federal Republic of Germany have seen a continuous positive evolution since the signing of a friendship treaty between the two countries in 1992. Additionally, on the occasion of the election of Frank-Walter Steinmeier as President of Germany in 2017, current Romanian president Klaus Johannis stated, among others, that: "[...] Last but not least, there is a profound friendship bounding the Romanians and the Germans, thanks mainly to the centuries-long cohabitation between the Romanians, Saxons, and Swabians in Transylvania, Banat, and Bukovina." Contributions to Romanian culture The German community in Romania has been actively and consistently contributing to the culture of the country. Notable examples include: Romanian architecture (e.g. the picturesque Transylvanian villages with fortified churches, known in German as kirchenburgen), or some of the most renowned castles as well as several medieval town centers with local markets, all of them highly popular touristic attractions); Romanian language (where approximately 3% of the words in the Romanian lexis are of German origin, mainly stemming from the influence of the Transylvanian Saxons and, later on, that of Austrians); Romanian literature (the first letter written in Romanian was addressed to the former early 16th century mayor of Kronstadt, Johannes Benkner, and the first Romanian language book was printed in Hermannstadt). The collections of Ottoman rugs kept in Transylvania inside several fortified churches (known as Transylvanian rugs) are associated with the Transylvanian Saxon Evangelical Lutherans. Royal House of Hohenzollern-Sigmaringen in Romania In the time of Romania's transition from a middle-sized principality to a larger kingdom, members of the German House of Hohenzollern (stemming from the Swabian Principality of Hohenzollern-Sigmaringen, part of contemporary Baden-Württemberg in south-western Germany) reigned initially over the Danubian United Principalities of Moldavia and Wallachia and then, eventually, also over the unified Kingdom of Romania both during the 19th and 20th centuries. Consequently, the ruling Romanian monarchs who were part of this dynastic branch were the following ones: Pretenders to the throne of Romania (after 1947, when King Michael I was forced to abdicate by the communists): Demographics Comparative demographic table (1930–2011) 1941 Romanian censuses In 1941, the initial number of all ethnic Germans in Romania amounted to as much as 542,325. Subsequently, however, in December 1941, after Romania created, incorporated, and administered the