Complex sentence: Outraged at the perceived challenge to its authority, the Catholic church encouraged a boycott of the schools so, though by 1883 3,885 secular schools had opened across the country, attendance in private Catholic schools had actually risen from 13% to over 60%.
Split into simpler sentences: Outraged at the perceived challenge to its authority, the Catholic church encouraged a boycott of the schools. Though by 1883 3,885 secular schools had opened across the country, attendance in private Catholic schools had actually risen from 13% to over 60%.