Shortly after the liberation of the city during the Latvian War of Independence on October 6, 1919, Jēkabmiesta State Secondary School was established in the school building of Jēkabmiesta District School at Pasta Street 1, which was the first real school in Jaunjelgava District at that time. The first principal of the school was Kārlis Lamberts, and the school had 12 teachers. The training took place in five classes with 185 students.