In 1995, the owner of the Cleveland Browns, Art Modell, announced that he was prepared to relocate the team to Baltimore.
Modell reached a tripartite agreement with the city of Cleveland and the League, where Modell was required to leave the team name, colors, and history all in Cleveland; a new Cleveland Browns team would inherit all of this in 1999. As for Modell, he would take the players, coaches, and his team culture to Baltimore to establish a brand new team.
And thus, the Baltimore Ravens were born.
In other words, the current Baltimore Ravens team in the League actually originated from the Cleveland Browns, but due to the tripartite agreement, the Browns' records and history were all left to the subsequent new team, and the Baltimore Ravens started from scratch, essentially a brand new team.
That's why the history of the Baltimore Ravens in the League has to start from the 1996 season.
But!