Gabrielius Landsbergis-Žemkalnis (1852–1916) was a Lithuanian playwright and activists of the early Lithuanian amateur theater. Born to an old noble family, Landsbergis attended Šiauliai Gymnasium where his friend Petras Vileišis encouraged him to speak Lithuanian and support the Lithuanian National Revival. After finishing a telegraph school in Riga in 1871, he worked at the telegraph offices in Moscow and Crimea. He returned to Lithuania in 1884 and joined the Lithuanian cultural life. He contributed articles to the illegal Lithuanian periodicals Varpas and Ūkininkas and his house was a gathering place of many Lithuanian intellectuals. Due to these activities, he was forced to leave Lithuania in 1894 but continued to maintain contacts with Lithuanian activists. He was arrested and impris