Who is Glaucias from The Campaigns of Alexander and what is their importance?

Glaucias is the king of the Taulantians. He is also one of the first rulers to encounter Alexander as he begins his conquests. Alexander's troops, though outnumbered, strike fear into the troops that Glaucias commands by performing impressively disciplined drills. The Taulantians retreat to inside their city, but then follow Alexander's troops as they withdraw. Alexander surprises Glaucias with a night attack. The surviving enemy soldiers scatter across the countryside.