The comments made by the cat about Porky's family are based on the old insult, "Ya Muddah wears army boots!"
Hamelin is an actual town in Germany. According to an old writing, "Hamelin's town in Brunswick, by famous Hanover city. The river Weser, deep and wide, washes its walls on the southern side."
According to a panel on City Hall, it was "erected MCDXXII", i.e., the year 1422.
The Supreme Cat's throne, under a canopy emblazoned with his epithet misspelled as "SUPREEM", sits on a crate marked on one end "Scrambells SOUP". This is a jocular turn on Campbell's Soups, a brand still sold today. The "Scrambells" is X'd out and the letters "REEM" are added to "SOUP" to form a second misspelled version of his highness's moniker.
The supreem cat looks like an early version of Sylvester, but speaks like Lou Costello.