In the last decades of the 19th century czar Alexsander III started the russification policy with the aim to assimilate all the nations of the empire into one. Because of that, in 1890 the school was renamed Revelskoje Petrovskoje Utšiliše. In 1890 the official language was changed to Russian although school officials had tried to delay it. In the previous year Wilhelm Petersen was appointed to the role of headmaster. He held that position until 1915 which makes him the longest serving headmaster in the school’s history.
The school uniform during that time consisted of a black coat, a leather belt with a golden plate and a black-and-orange hat which had crossed oak tree leaves and letters ,, РПУ’’ (RPU) in the front.
As a result of the 1905 revolution, students became more and more politically active. They took part in strikes and started a secret group called Kommuuna. In 1906 Estonian became an extracurricular subject.
In 1918 the school was divided in two ㅡ Estonian Science School and German Science School.
Extracurricular activities were also popular in the Secondary School of Science: orchestra, student choir, acrobatics, soccer, fencing and wrestling which brought up a famous wrestler Georg Lurich.