A brief history of the Castle Project is also available on Wikipedia.

Castle was born from the Apache Avalon project in mid 2003 as an attempt to build a very simple inversion of control container. The overall design was the result of more than a year in contact with masters of the Avalon land like Carsten Ziegeler, Leo Sutic, Leo Simons and Berin Loritsch to name a few.

After several discussions about what a useful container must solve, Castle Windsor’s first draft was created. Several changes (and rewrites) have taken place before reaching its current form.

However, Castle had a more ambitious agenda. Tools like DynamicProxy were used by several projects and a proper home to support those users and build a community around them was necessary. Along the same lines, these tools had nothing in common with Avalon’s mission, so we had to find a more suitable home for them.

Since then a new mission came, and new projects flourished. The Castle team is as concerned with the quality of the projects as it is concerned with the health of its community.