Definition: Rewrite each original sentence in order to make it easier to understand by non-native speakers of English. You can do so by replacing complex words with simpler synonyms (i.e. paraphrasing), deleting unimportant information (i.e. compression), and/or splitting a long complex sentence into several simpler ones. The final simplified sentences need to be grammatical, fluent, and retain the main ideas of their original counterparts without altering their meanings.
Input: The formation of Armenian revolutionary groups began roughly around the end of the Russo-Turkish War of 1878 and intensified with the first introduction of Article 166 of the Ottoman Penal code 166, and the raid of Erzerum Cathedral.

The creation of Armenian revolutionary groups began around the end of the Russo-Turkish War of 1878.  The war intensified with the first introduction of Article 166 of the Ottoman Penal code 166, and the raid of Erzerum Cathedral.