Unlike other Taliban groups, the Haqqanis' approach to mayhem was worldly and sophisticated: they recruited Arabs, Pakistanis, even Europeans, and they were influenced by the latest in radical Islamist thought.
For years, Hizb-I-Islami fighters have had a reputation for being more educated and worldly than their Taliban counterparts, who are often illiterate farmers.
When US-led forces toppled the Taliban government in November 2001, Afghans celebrated the downfall of a reviled and discredited regime.