Complex sentence: Kenney was first elected to the House of Commons in 1997 at the age of 29 as a member of the Reform Party of Canada (1997--2000), which became the Canadian Alliance (2000--2003).
Split into simpler sentences: Kenney was first elected to the House of Commons in 1997 at the age of 29. He was a member of the Reform Party of Canada (1997--2000), which became the Canadian Alliance (2000--2003).