Complex sentence: Most notably, in 1725, they annihilated a party of 200 men gold-seekers on the river in 1725 and in 1730,800 or more Payaguá warriors killed most of a party of 400.
Split into simpler sentences: Most notably, in 1725, they annihilated a party of 200 men gold-seekers on the river in 1725. In 1730,800 Payaguá warriors killed most of a party of 400.