Complex sentence: Due to Marius' bishopric closeness to northern Italy, the chronicler had easily access to information regarding northern Italy and thus, according to Roger Collins, his brief work must be considered to a degree authoritative.
Split into simpler sentences: Due to Marius' bishopric closeness to northern Italy, the chronicler had easily access to information regarding northern Italy. For this reason, according to Roger Collins, his brief work must be considered to a degree authoritative.