The History page is, as its name suggests, the place where you can view a list of all the profiles you have written to or dismissed.
To get here, select Members from the top menu, then History from the submenu.
If you sent someone a Message, a purple envelope will appear next to their profile.
You will also notice filters on this page, as shown below. They include All, Messaged, and Dismissed.
Select a filter to bring up the list of people within that category. For example, if you would like to see a list of all the people you have messaged, select the Messaged button. If you would like to see who you have dismissed, you can do so by selecting the Dismissed button.