Complex sentence: The two most noted are Manuscripts of the "Cloud" are British Library MS Harleian 674 and Cambridge University Library Kk.vi.26: these contain all seven of the works attributed to the "Cloud"-author, the former extensively glossed in Latin.
Split into simpler sentences: The two most well known are British Library MS Harleian 674 and Cambridge University Library Kk.vi.26. These contain all seven of the works attributed to the "Cloud" author, the former extensively glossed in Latin.