Complex sentence: Perhaps his most memorable contribution to politics was during the crisis over the People's Budget of 1909-10, where the House of Lords, violating a convention going back more than 200 years, rejected the Budget.
Split into simpler sentences: Perhaps his most memorable contribution to politics was during the crisis over the People's Budget of 1909-10. The House of Lords, violating a convention going back more than 200 years, rejected the Budget.