Between 1664 and 1672, however, William Morgan decided to rebuild the house on a larger scale from red brick, at that time a rare building material in Wales.

The architect of the enlarged house is not known for certain, but John Newman follows Howard Colvin's suggestion that the design was by Roger and William Hurlbutt, who had worked in a similar style at Ragley Hall and Warwick Castle.

[1] In his 1882 publication, local historian, and brother of the first Lord Tredegar, Octavius Morgan, provides a plan of an intricate garden maze which was in place prior to the 1660s improvements and which probably dated from the time of Queen Elizabeth I.

Tredegar House, set in 90 acres which remains landscaped for ornamental purposes, with less agriculture than in previous centuries, is the finest Restoration house in Wales and for over five hundred years the estate (including Ruperra Castle) was home to the Morgan family, later Lords Tredegar.

Sir John received reward for his early support, and on 7 November 1485 he was appointed by the new king to the office of ‘Sheriff of Wentloog and Newport’ and made ‘Steward’ of the Machen Commote.

His elevation to officer of the Tudor crown placed Sir John Morgan's influence and power at new heights.

After the King's arrest and execution, he fled to the continent and married Anna Petronilla the daughter of Baron von Pöllnitz from Westphalia (Governor of Lippstadt, 20 miles (32 km) east of Dortmund in Germany).

Their fortunes continued to flourish down the generations, tremendously enhanced by the foresight and business enterprises of Sir Charles Morgan, 1st Baronet throughout the 18th century.

Following his father's financial successes, his son Sir Charles Morgan, 2nd Baronet further expanded several commercial and industrial projects, and virtually established Newport as an important trade centre.

Following a trip to Lourdes for religious guidance, John Morgan, a recent catholic convert, sold Tredegar House to the Catholic Church for use as a convent school with boarders, run by the Sisters of St Joseph, asserting the sale was “good for his bank balance, and his soul”.

In 2014 an episode of the Antiques Roadshow was filmed at the property and the house's red brick exterior now features in the programme's opening sequence.

[citation needed] The television series Being Human, Da Vinci's Demons and The Hairy Bikers have all used the house as a location.

Since the programme was revived in 2005, many episodes of Doctor Who have used Tredegar House for location filming, including "The Christmas Invasion" in 2005; "New Earth", "Tooth and Claw", "The Girl in the Fireplace" and "Army of Ghosts" / "Doomsday" in 2006; "Human Nature" / "Family of Blood" in 2007; "The Unicorn and the Wasp" and "The Next Doctor" in 2008; "The End of Time" in 2009–10; "The Impossible Astronaut" in 2011; "The Woman Who Lived" in 2015; "Spyfall, Part 2" in 2020; and "Rogue" in 2024.

[citation needed] For many years an annual vintage car rally was held in the grounds in order to raise funds for Leukaemia Research.