Complex sentence: In 1997 and in 2003 Roman ships were discovered in the neighbourhood of De Balije and in 2002 and 2003 Roman watchtowers were discovered in the neighbourhoods of Vleuterweide and Het Zand.
Split into simpler sentences: In 1997 and in 2003 Roman ships were discovered in the neighbourhood of De Balije. In 2002 and 2003 Roman watchtowers were discovered in the neighbourhoods of Vleuterweide and Het Zand.