Complex sentence: Colonel Henrich Danckwardt, commander of Carlsten had on June 27 requested an additional 400--500 men, to prevent an invasion of Koön and Klåverön (south of Marstrand) but the soldiers did not arrive before Tordenskjold had launched his attack.
Split into simpler sentences: Colonel Henrich Danckwardt, commander of Carlsten had on June 27 requested an additional 400--500 men to prevent an invasion of Koön and Klåverön (south of Marstrand). The soldiers did not arrive before Tordenskjold had launched his attack.