[Spoilers] The relation between ragnar and ecbert

I never understood the relationship between ragnar and ecbert. I’m re-watching the series for 3rd time and still get confused with every watch. Like they have met each other on screen for about 5 episodes but the amount of respect ecbert has for ragnar is off the charts and I don’t understand why? Like after ragnar’s death he was broken, just like how ragnar was broken after athelstan death. Help me understand this.