In 2002, Tim Kemp found that Subversion was a very good version control system, but it lacked a good GUI client. The idea for a Subversion client as a Windows shell integration was inspired by the similar client for CVS named TortoiseCVS.
Tim studied the source code of TortoiseCVS and used it as a base for
TortoiseSVN. He then started the project, registered the domain
tortoisesvn.org
and put the source code online. During that time,
Stefan Küng was looking for a good and free version control system
and found Subversion and the source for TortoiseSVN. Since TortoiseSVN
was still not ready for use then he joined the project and started
programming. Soon he rewrote most of the existing code and started
adding commands and features, up to a point where nothing of the
original code remained.
As Subversion became more stable it attracted more and more users who also started using TortoiseSVN as their Subversion client. The user base grew quickly (and is still growing every day). That's when Lübbe Onken offered to help out with some nice icons and a logo for TortoiseSVN. And he takes care of the website and manages the translation.