The BackTrack distribution originated from the merger of two formerly competing distributions which focused on penetration testing: WHAX: a Slax-based Linux distribution developed by Mati Aharoni, a security consultant. Earlier versions of WHAX were called Whoppix and were based on Knoppix.

When did BackTrack become Kali?

BackTrack was based on Slackware from v1 to v3, but switched to Ubuntu later on with v4 to v5. Using the experience gained from all of this, Kali Linux came after BackTrack in 2013.

Why was BackTrack discontinued?

The backtrack project had to be shut down and moved to the Kali Linux project. This happened because the team wanted a strong and rolling base to work on. The work on Backtrack was stopped and the newer Kali OS based on Debian was launched in 2013.