I am trying to construct a timeline of Prophet Muhammad (peace be upon him). Specifically, the last time he was in *itikaf*. I am sure there are English sources out there, but my (very) quick search, I did not come across one. I used an [online calculator](https://www.searchtruth.com/hijri/) and I found that it should be between December 20 631, and December 30. Can somebody confirm that?