Complex sentence: Despite fading from contemporary Singaporean society, these secret societies hold great relevance to Singapore's modern history since the founding of the city state in 1819, which saw the arrival of thousands of Chinese, thereby transplanting social systems already present in China itself.
Split into simpler sentences: Despite fading from contemporary Singaporean society, these secret societies hold great relevance to Singapore's modern history. The founding of the city state in 1819 saw the arrival of thousands of Chinese, thereby transplanting to Singapore social systems already present in China itself.