Tree-ring data from papers other than the infamous Mann Hockey Stick paper extend the data to about the year 800 (Esper et al, 2002; Frank et al 2007), clearly showing a medieval warming period (MWP) around 1000 and a cool period between 1200-1800, the "little ice age" (LIA), with subsequent recovery from the LIA in the 19-20th centuries. Remember the infamous Mann email stating "...it would be nice to "contain" the putative 'MWP'"?
"Bottom line - their [sic] is no way the MWP (whenever it was) was as warm globally as the last 20 years. There is also no way a whole decade in the LIA period was more than 1 deg C on a global basis cooler than the 1961-90 mean. This is all gut feeling, no science, but years of experience of dealing with global scales and varaibility [sic]." - Phil Jones email