Complex sentence: He was elected to the Irish House of Commons for Baltimore in 1783, a seat he held until 1790, and then represented County Donegal in the British House of Commons from 1801 to 1806.
Split into simpler sentences: He was elected to the Irish House of Commons for Baltimore in 1783, a seat he held until 1790. He sat then for County Donegal in the British House of Commons from 1801 to 1806.