Finding the oldest article on a topic can be difficult. Keep in mind that the database you use needs to:
If you know a key researcher in your field, you can try an author search.
Once you've found your modern and/or seminal article, look for the oldest cited article in that paper.
When using Google Scholar at home, go to Scholar Preferences, library links, and search for and select CSULB. Now in your search results you will have GetIt@CSULB links to access CSULB subscriptions for full-text articles. See this how-to video for more info.