Complex sentence: More lasting and of more economic impact were canals like the Naviglio Grande built between 1127 and 1257 to connect Milan with the Ticino River, the most important of the lombard "navigli", and the oldest functioning canal in Europe.
Split into simpler sentences: More lasting and of more economic impact were canals like the Naviglio Grande built between 1127 and 1257 to connect Milan with the Ticino River,. The Naviglio Grande is the most important of the lombard "navigli", and the oldest functioning canal in Europe.