BEIRUT (AP) — Over the past dozen years, Syrian militant leader Abu Mohammed al-Golani has worked to remake his public image and the insurgency he commands, renouncing longtime ties to al-Qaida and consolidating power before emerging from the shadows.

Now al-Golani, 42, seeks to seize the moment yet again, leading his fighters in a stunning offensive that has put them in control of Syria’s largest city, reigniting the country’s long civil war and raising new questions about President Bashar Assad’s hold on power.

The surge and al-Golani’s place at the head of it are evidence of a remarkable transformation. Al-Golani’s success on the battlefield follows years of maneuvering among extremist organizations while eliminating competitors and former allies.

Along the way he moved to distance himself from al-Qaida, polishing his image and his extremist group’s de-facto “salvation government” in an attempt to win over international governments and the country’s religious and ethnic minorities.

Putting himself forward as a champion of pluralism and tolerance, al-Golani’s rebranding efforts sought to broaden his group’s public support and legitimacy.

Still, it had been years since Syria’s opposition forces, based in the country’s northwest, made any substantial military progress against Assad. The Syrian president’s government, with backing from Iran and Russia, has maintained its control of about 70 percent of the country in a stalemate that had left al-Golani and his jihadi group Hayat Tahrir al-Sham, or HTS, out of the spotlight.