A rebellion started in 1400, during the rule of Henry IV. It was started by Owain Glyndŵr. This was just after Richard was told he was no longer king. Two cousins of Owain Glyndŵr, Rhys ap Tudur and his brother Gwilym, attacked the castle as a surprise. They dressed up like carpenters and acted like they were going to fix the castle. The got inside, killed two watchmen, and took over the castle. Their troops took over the town. The brothers lived there for about 3 months. They gave up after Henry IV promised to forgive them and they would not go to trial.
The castle was almost used during the War of the Roses but by the time the war ended it did not see any activity. The castle went through repairs in the 1520s and 1530s by Henry VIII. The castle was used as a prison and sometimes people who visited Conwy stayed at the castle.
The castle had fallen apart again by the 1600s. It was sold to Edward Conway by Charles I in 1627. Edward bought it for £100. Edward's son, also named Edward, took over the castle in 1631. It was a ruin. In 1642, the English Civil War started. John Williams, Archbishop of York, took charge of the castle for the king. He used his own money to fix the broken parts of the castle. In 1645, Sir John Owen became governor of the castle. The two men argued about this, since Williams was supposed to be running it, not Owen. Eventually Williams gave up and moved back to London. The castle was taken over by Thomas Mytton between a siege in August and November of 1646.
After the siege, Colonel John Carter became governor of the castle. He made more repairs to fix it. In 1655, the English Council of State was told, by the Parliament of England, to pull down the castle so people could not use it anymore. The Bakehouse Tower was partially torn apart during that time. The castle was given back to Edward Conway by Charles II as part of the Restoration. But, five years later Conway took all of the iron and lead that was on the castle and sell it to make money. A man named William Milward was in charge of taking the iron and lead off the castle. The people who lived in the town of Conwy protested the removal. Conway and Millward did not care and the castle became a complete ruin.
By the end of the 18th century the castle ruins were called "picturesque" and beautiful. People and artists would visit the castle from around the country. Artists would paint pictures of it, including the artists Thomas Girtin, Moses Griffith, Julius Caesar Ibbetson, Paul Sandby and J. M. W. Turner. Bridges were built over the River Conwy to the town from the Llandudno in the 1800s. The new bridges brought more tourists to the area. The two bridges included the Conwy Suspension Bridge, built in 1826, and the Conwy Railway Bridge, built in 1848. This allowed people with boats, cars, and riding in trains to visit the castle. The Holland family was running the castle, and in 1865 they gave it to the local government to run. The town helped to restore the ruins and they fixed the Bakehouse Tower. The castle was leased in 1953 to the Ministry of Works. They had Arnold Taylor start to fix the castle. He also researched the castle's history. A new road was built to the castle in 1958. It was going to be made into a monument by the country. In 1986 it was called a World Heritage Site.
Today it is ran by Cadw and tourists visit it. As of 2010, 186,897 people had visited the castle. They opened a new visitor center in 2012. The castle always has to be repaired. Between the years 2002 and 2003, it cost £30,000 to maintain and repair the castle.
The castle is considered one of the best "examples of late 13th century and early 14th century military architecture in Europe," by UNESCO. It sits on the coast. The coast is made up of a lot of rocks, including grey sandstone and limestone. Most of the stone that the castle was built out of is from this stone. The sandstone used to make carvings was brought from the Creuddyn peninsula, Chester, and the Wirral. That sandstone had more colors than the grey sandstone that was local. It might have been chosen not only because it was easy to carve, but also because it was pretty.
The castle is rectangular. It has two different sections, the Inner Ward and the Outer Ward. It has four towers. They are and there is one on each side of the castle. The castle would have been painted white with lime render during its early days. The towers have holes in them, called "putlog holes". These holes were used to help the builders build the towers, by putting wood timber pieces through the holes so they could climb up the towers. There are also square holes that are found in the castle walls. No one knows what they were used for. Maybe they were used to get rid of water when it rained, used for hoardings, or for displaying decorations.
The main entrance to the castle is through the western barbican. That barbican used to go over a drawbridge and a ramp from the town. Today, the path goes along the east side of the walls. The barbican has some of the oldest machicolation stones in Britain. In the early days, the gate to the castle was probably protected by a portcullis.
Through the gate is the Outer Ward. When it was first built, this is where administrative duties were. People were handling business and management of the castle. This is where the northwest tower is located. People could live inside of it, and also store things. There is also the southwest tower, which was used by the constable. There was also a bakery inside of it. On the southside of the Outer Ward, there is a great hall and a chapel. There are also cellars. There is an old great arch from the 1340s. A jail was in a tower behind the great hall. There was a dungeon inside of it. The north side of the Outer Ward has a kitchen, brewery, bakery, and inside the tower people could live and store things.
There used to be a wall that separated the Inner Ward from the Outer Ward. The wall, which was inside the castle, had a drawbridge and a gate. There was also a ditch which made it hard to cross if the gate was closed. In the 16th century, the ditch was filled up so people could walk over it and the drawbridge was removed. This is where the spring that the castle gets it water from is located. The well is deep. The Inner Ward is where the royal guests and residents lived. It is also where their staff and servants lived. The royal bedrooms, also called "chambers", are considered the finest preserved in England and Wales. The Inner Ward was supposed to look like a very small version of a royal palace. The reason the wall, gate, and ditch were built was so that if there was an emergency or an attack, the Inner Ward could be sealed off from the Outer Ward, which would fight against invasions.
The rooms where the royals lived were on the first floor in a series of small buildings. There were four protective towers for the Inner Ward. One of the towers was a chapel where the royals would have religious services. All of the towers had turrets for security. They also each displayed the royal flag. It is believed that this part of Conwy Castle was designed similar to that at Corfe Castle. The king could have his own private time while having a lot of security to keep him and all inside safe. There used to be two apartments inside, but eventually they were made into one apartment with three rooms.
The east side of the Inner Ward has another barbican. This is where the castle garden is. The royal apartments could see the garden from their windows. There used to be grass there, and then vines, crab-apple trees, and flowers. There was a small gate that led to a small dock on the river. This allowed visitors to visit and leave the castle with very few people seeing them. It also allowed people to get supplies for the Inner Ward from boats.