Complex sentence: In 1719, he constructed the Chancery Building on Slotsholmen and, for a period beginning in 1731, he headed the construction work at Hirschholm Palace to the north of Copenhagen.
Split into simpler sentences: In 1719, he constructed the Chancery Building on Slotsholmen. From 1731, he spent a number of years coordinating the construction of Hirschholm Palace to the north of Copenhagen.