M.H.
My son is 15 months now but he was about your sons age when we started establishing a bedtime for him. We set his at eight. On mornings I work I wake him up at ten til seven and on the weekends he'll sleep till about seven thirty. At first it was a little painful because he would scream when we put him to bed, but after a while he eventually got used to it, and now goes to bed every night at eight with no problem. He also started waking up in the middle of the night after he was sleeping through the night with no problem. I know it sounds harsh but I would just let him cry himself back to sleep. As my mother put it he's training you instead of the other way around. If you get up with him every time he crys he's going to get used to it and continue doing it. You have to stay strong and remember that he's going to cry but he will get used to it and he'll be okay. Hope this helps
M.