Complex sentence: Prior to the formation of Rival Sons, Jay Buchanan recorded as a solo artist, as well as with his band Buchanan, which had previously released "'All Understood"' in 2004 and "True Love EP" in 2006.
Split into simpler sentences: Prior to the formation of Rival Sons, Jay Buchanan recorded as a solo artist and with his band Buchanan. The Buchanan band previously released "'All Understood"' in 2004 and "True Love EP" in 2006.