On a small island in the middle of the Irish Sea, fortresses preside over the rugged shores. This unlikely location was the birthplace of a medieval empire that lasted 200 years, ruled by a dynasty of sea kings. The first of these kings was Godred Crovan, a notorious warlord descended  from Irish and Viking rulers. Starting in 1079,  Godred consolidated power over the Isle of Man and the Hebrides, a collection of islands off the west coast of Scotland. He seized control of important  sea routes between the British Isles, Scandinavia, and the North Atlantic. A turbulent period followed Godred’s death, characterised by invasions from Norway and Ireland, and intense feuding between princes. But his descendants held on to power, building coastal fortresses, roving the seaways, throwing themselves into epic battles, and consolidating control  over an impressive maritime kingdom. The inhabitants of this kingdom had both Gaelic and Norse roots, and many probably spoke both languages. Those on the Isle of Man were known as the Manx people, while those in the Hebrides were known as Islanders or People of the Isles. Though we still don’t know  for sure how many there were, we do know this relatively small group had an outsize impact on the region. Perched on cliffs with sweeping views  and safe harbors, seaside fortresses helped the kings control shipping, commerce, and resources. The empire commanded vast fleets of Viking-style long ships, which they used for trading, raiding, and plundering the seas. Observing this prowess,  many neighboring rulers sought their aid. The brothers Rognvald and Olaf  each solved neighbors’ maritime woes: King Rognvald supplied military assistance to the Scottish king, and King Olaf’s forces  served as a Coast Guard at the English King Henry III’s request— for a hefty fee. The sea kings also sparred  with their powerful neighbors, but they had a particularly bitter rivalry with another dynasty in their own isles: a line of rulers in the Hebrides. In the 1150s, a chieftain of this line, Somerled, defeated the Manx King,  his brother-in-law, in a naval battle and formed a rival Kingdom of the Isles, fracturing the old kingdom. This began a century-long rivalry between Somerled’s line, who ruled the southern  and central Hebrides, and the Manx Kings, who ruled  the Isle of Man and northern Hebrides, to control the seaways. Family feuds often blossomed into bitter civil wars. In 1223, King Rognvald sent  a letter to his son commanding him to murder  his uncle Olaf. When Olaf discovered the plot, he launched a vicious attack on his nephew, blinding and mutilating him. After Rognvald’s death  several years later, people realized the letter ordering  the attack might have been forged. The Manx kings attempted to resolve  disagreements at Tynwald, an open-air parliament  centered on a mound, where assemblies ruled on matters  of justice and other issues. Such sites were commonly used in the Viking world for resolving anything from local disputes to matters involving kings. These meetings didn’t always go smoothly— sometimes violence erupted, and in 1237, two rival factions squabbled  to the point of breaking up the assembly at Tynwald. The four-tiered mound at Tynwald  survives to this day, and the modern Manx parliament still holds an annual meeting there. In 1248, King Harald of Man died in a shipwreck and was succeeded by his brother. Weeks into the new king’s reign,  a rebel knight assassinated him. His brother Magnus died in 1265  at Castle Rushen— without an heir. According to one scribe, his death marked  the day that “kings ceased to reign in Man.” Scotland annexed Man and the Isles  the next year, in 1266. We know about the exploits of the  sea kings primarily from a chronicle written by Christian scribes living  on the Isle of Man, and from the praise poems composed  to celebrate the kings’ victories. Today, although the sea kings are long gone, their presence remains etched onto the landscape.