I'm currently learning to create themes in WP but I'm a little confused. I created my HTML/CSS page and then I started converting it into a WP theme using an empty theme from starkers which contains a lot of pre-made themes like page.php, archives.php, comments.php etc, but I noticed that WP was ignoring the index.php template which should contain the main content and that was driving me crazy so I decided to start from scratch and then I started deleting all templates except the four basic ones (header.php, index.php, sidebar.php and footer.php) and as soon as I deleted them my theme worked just as it should, then I put all the templates back into the theme's folder and again the page wasn't behaving as it should, so I started deleting the extra templates one by one to find the one causing the problem and I found that the one causing the problem was the page.php, I deleted only this template and the theme now works just fine. It looks like it was showing the page.php instead of the index.php which doesn't have a sidebar. The problem is now solved but I would like to know how this happen because now I won't be able to use the page.php if I would need to. May be I changed the settings in the Admin area to use a different template? If yes, where is this option?
Any idea why or what was causing the problem?