Complex sentence: All four clubs are the only Spanish clubs to have won five or more international trophies, while Real Madrid, Barcelona and Valencia are also in the top ten most successful clubs in European football in terms of total European trophies.
Split into simpler sentences: All four clubs are the only Spanish clubs to have won five or more international trophies. Whilst, Real Madrid, Barcelona and Valencia are also in the top ten most successful clubs in European football in terms of total European trophies.