Master Page Life Cycle

Master Page sequence of events / Life Cycle

1) Master Controls Init
2) Content Controls Init

3) Master Page Init
4) Content Page Init

5) Content Page Load
6) Master Page Load

7) Master Controls Load
8) Content Controls Load

9) Content Page PreRender
10) Master Page PreRender

11) Master Control PreRender
12) Content Control PreRender

13) Master Controls Unload
14) Content Controls Unload

15) Master Page Unload
16) Content Page Unload

--Kishore

For more detailed explanation about Master & Content page event. Go through the below link

http://odetocode.com/articles/450.aspx
http://englestone.blogspot.com/2008/06/master-page-sequence-of-events.html