Complex sentence: Having recorded and toured with the band in the early days, Aurora Dawn rejoined the band in 2009, and some time between late 2010 and early 2011, programmer, harmonicist, and founding member Piers "Mountain of Love" Marsh left the band.
Split into simpler sentences: Having recorded and toured with the band in the early days, Aurora Dawn rejoined the band in 2009. Between late 2010 and early 2011, programmer, harmonicist, and founding member Piers "Mountain of Love" Marsh left the band.