Complex sentence: The disastrous rule of the last Comnenian emperor Andronikos I (r.1183--1185) worsened the situation of the Bulgarian peasantry and nobility and the first step of his successor Isaac II Angelos was to impose an extra tax for his wedding.
Split into simpler sentences: The disastrous rule of the last Comnenian emperor Andronikos I (r.1183--1185) worsened the situation of the Bulgarian peasantry and nobility. His successor Isaac II Angelos' first act was to impose an extra tax for his wedding.