Complex sentence: Under his leadership the Museum has received a record number of 3.8 million visitors and reopened the Europe 1600-1815 galleries in 2015, and the Rosalinde and Arthur Gilbert Galleries in 2016.
Split into simpler sentences: Under his leadership the Museum has received a record number of 3.8 million visitors. It opened the Europe 1600-1815 galleries in 2015, and reopened the Rosalinde and Arthur Gilbert Galleries in 2016.