Coins in the river

Once upon a time in an ancient kingdom, lived twenty lords, all equally rich.

As the years passed, they came to die, one at once. The gold coins of the deceased were then equally split among the still living lords. As for the remaining coins that could not be equally split, it had been decided that they would be thrown in the river, to prevent conflicts.

The time flew by, until only one lord was left.

Many many years later, one found two chronicles telling those events.
According the first chronicle, 172 gold coins had been found in the river.
According the second chronicle, no gold coin had ever been thrown in the river.

1. Which one of the two chronicles is necessarily false?
2. Assuming that the other one is true, what was the minimal wealth or each twenty lords?