Phoenix house to be

At Hogwarts were there only 4 houses until a muggle born witch found out before school started that their was a fifth founder of Hogwarts was Elanora Phoenix a muggle who were friends with the 4 founders until her head was cut of by no other than Salazar . The only reason why is because she was like all 4 founders smart like Rowena,brave like Godric , as patient like Helga and a good leader just like Salazar.
and they could not teach their students to in brace all four so what will happen if the muggle tells anyone about it find out in Phoenix house to be