It is well known that Lord Shani is son of Surya.
There is a famous story that when Shani dev opened his eyes as a baby for the very first time, the sun went into an eclipse.
Here is one more interesting mentioning about Shani and Surya in Shani Chalisa
रवि कहं मुख महं धरि तत्काला । लेकर कूदि परयो पाताला ॥
This loosely translates to :
Swallowing the Sun(Surya), you(Shani) went to third world(पाताला )
Does this mean there was quarrel between Shani Dev and Surya dev?
What was the reason that Shani took Surya to third world(पाताला)?