Two portraits of Robert Plant: One, the most familiar, at least to those who still picture him as the once and always Led Zeppelin front man, a bare-chested banshee with a mop of blond curls, strutting and posturing at the microphone stand as his band wails relentlessly behind him. The other, an aging, wizened troubadour, still at the helm but considerably more subdued, asserting himself distinctly but showing restraint in deference to the music and his musical companions.
• Plant's earliest influences went to the heart of American roots music - bluesmen like Robert Johnson, Bukka White and Skip James - and their music informed Led Zeppelin right from the beginning. Songs like "Dazed and Confused," "Traveling Riverside Blues" and "Babe, I'm Gonna Leave You" were a direct lift from an American blues traddition.
• While country music might not have been a direct part of Zeppelin's repertoire, the music of his homeland certainly was, and the strains of British folk music that seeped into the early traditional music of the American south is undeniable. Led Zeppelin 3 in particular marked a turn in Plant's trajectory that could be directly traced to the mellower muse that's caught up with him more recently. That's particularly true of songs like "Gallows Pole," "Thank You," "Over the Hills and Far Away" and "Tangerine," songs he still performs in his current sets because they fit so seamlessly. "Going to California" is another track that would seem to bridge the divide.
• Plant had another notable duet before he hooked with Alison Krauss, and it found him taking a similar stance. He partnered with the late Fairport Convention singer Sandy Denny on the Led Zep song "Battle of Evermore." That led to another connection that lingers to this day; Plant and the Band of Joy include a snippet of Fairport's immortal anthem "Come All Ye" in their set.
• Plant's fondness for seminal '60s music was well established early on, but on his 2007 solo album Dreamland he covered a number of classic roots rock songs -- among them Tim Rose's "Morning Dew," Tim Buckley's "Song to the Siren," the Youngbloods' "Darkness Darkness" and Bob Dylan's "One More Cup of Coffee." It was an ideal segue way into his Krauss collaboration Raising Sand, which was released later that year and spawned from a similar songbook of Americana influences.