Snapedom

The Potterverse history of Wizarding Britain goes back to the days of Merlin, in the early 6th century CE. The history of Hogwarts Houses goes back to the founders, somewhere in the (late?) 10th century CE. However we only have snippets of that history in canon and semi-canon (and much of that is about Quidditch). We know the official reason that Salazar Slytherin left the school had to do with accepting Muggle-born students to the school. We have some idea about the times of the first Voldemort war and a more detailed (but still incomplete) view of Harry's years at Hogwarts. But what happened from the time Salazar Slytherin left and the meeting between Albus Dumbledore and Tom Riddle in the Headmaster's office, shortly after Dumbledore's appointment as Headmaster and Riddle's return from 10 years of travels? Was the House of Slytherin always in opposition to the other Houses? Was objection to Muggle-borns always characteristic of Slytherin House while the other Houses were always open to them or were there times when anti-Muggle-born sentiment was common in other Houses as well, or even times when Slytherin House was the most open-minded? Where did the Sorting Hat place ambitious and cunning Muggle-borns? Was the trend towards increasing levels of secrecy and isolation from the Muggle world promoted more by one House than others or was it a general trend of all Wizarding Britain? Did acceptance of Muggle-borns at Hogwarts continue unperturbed throughout the centuries or were there times they were excluded - for example immediately after the passing of the Statute of Secrecy? What were House relationships like under a Slytherin Headmaster such as Phineas Nigellus Black? Support your ideas with canon and semi-canon evidence.