Complex sentence: Upon the founding of Halifax (1749), Acadians and Mi'kmaq conducted twelve raids on the capital region; the most significant raid was the one in 1751 on Dartmouth.
Split into simpler sentences: Upon the founding of Halifax (1749), Acadians and Mi'kmaq conducted twelve raids on the capital region (Halifax/Dartmouth). The most significant raid was the one in 1751 on Dartmouth.