Complex sentence: Soon after they met, the two became close friends and Woodhouse started to collect Keatsiana, documenting as much as he could about Keats's poetry, an archive that survives as one of the main sources of information on Keats's work.
Split into simpler sentences: Soon after they met, the two became close friends, and Woodhouse started to collect Keatsiana, documenting as much as he could about Keats's poetry. This archive survives as one of the main sources of information on Keats's work.