There is no evidence that Barbara Allen or Lord Randall's unnamed lover killed anyone.

Barbara Allen, sure. But all three versions of Lord Randall in DT are pretty clear on him being murdered by poison (by his lover in 1 and 3, stepmother in 2).

http://www.mudcat.org/@displaysong.cfm?SongID=3723
http://www.mudcat.org/@displaysong.cfm?SongID=9882
http://www.mudcat.org/@displaysong.cfm?SongID=9883

Colyn, as regards "seeing out their 3-score-and-10", in pre-medical times if you'd made it to 40 then odds were fairly good that you'd make old bones. The majority didn't reach 40 though. The stats make this pretty clear, when 10 children was the norm and the average survival rate to reproduction was only a little over 2. Also, those reaching 40 were usually richer; all manual occupations were significantly dangerous, as was warfare (a major source of male mortality for most of history).

Graham.