How did the daggers turn into dining knives and is it true that the tips rounded to avoid drinking duels?
Rounded table knives really started using French aristocrats in the era of Cardinal Richelo, in the XVII century. However, they appeared much earlier. This is confirmed by this, in particular, knives from the castle of the Dukes of the Burgundy, dated 1429, that is, the first third XV century. Their appearance practically matched modern. Therefore, it is assumed that Cardinal Richelieu came up with and introduced a new shape of the knives into appeal, incorrectly. But it was he who promoted her spread in France. (By the way, you know why in the world is eating not only a spoon and fork?)
There are too many aristocrats that are supporting royal power in noble disassembly. Cardinal called such collisions "stabbing"
Arman Jean du Plesi, Duke de Richelo, more famous as Cardinal Rieshelo, was the first Minister of King Louis XIII, that is, the head of the government of France. It was forbidden a duel, rightly believing that too many aristocrats who are supporting royal power dies in noble disassembly. Cardinal called such collisions "stabbing". Quarrels happened including during the feast. In this sense, when conflict situations occur, the replacement of a combat knife on a table did a meal more secure. (Read the Overview of My Planet "Ten famous duels".)