Archaeologists have discovered the remains of Henry the VIII's ship, the "Mary Rose" and done a ton of research on what they've found. Among the items they recovered were dozens of preserved bow staves for longbows. If I remember correctly, the estimated pull was in the upper 100s to lower 200 pound range. They also recovered skeletal remains of presumed archers, based on the bone development in the shoulder area. I remember one researcher describing their shoulders as "gorilla-like" , but he was probably exaggerating a little. There's a ton of interesting info on the Mary Rose, if you're interested.
I found a cross section of a yew limb to better show how they built those bows:
