The story of the Sage matroid package

In 2010, Stefan van Zwam and myself started work on on a new package for computing with matroids in Sage, the open source mathematics platform. I want to tell the story of this project: the theoretical goals that motivated us spending that much time on writing software, our design principles, and our considerations when choosing Sage as a platform. Finally, I want to discuss some of the insights gained from working on this software.