Complex sentence: In 1630, Philip IV of Spain and Charles I of England signed the Treaty of Madrid ending the war which had proven a costly fiasco for England and Scotland, but merely a minor distraction for the Spanish and French who were occupied by the wars engulfing Europe.
Split into simpler sentences: In 1630, Philip IV of Spain and Charles I of England signed the Treaty of Madrid, ending the war. It had proven a costly fiasco for England and Scotland, but merely a minor distraction for the Spanish and French who were occupied by the wars engulfing Europe.