Complex sentence: Farah later appeared in Zürich at the 2014 European Athletics Championships; he successfully defended his 5,000m title and won a gold in the 10,000m, thus completing another major championship double.
Split into simpler sentences: Farah later appeared in Zürich at the 2014 European Athletics Championships. He successfully defended his 5,000m title and won a gold in the 10,000m, thus completing another major championship double.