Masters records that he was expelled by Echmarcach, who was then elected king by the Dubliners. The Annals of Tigernach, on the other-hand, simply state that Echmarcach succeeded Ímar. Echmarcach may well have controlled Mann throughout his second reign in Dublin. Silver hoards uncovered on Mann, dated by their coins to the years 1030s–1050s, may well be the by-product of the intense conflict over control of the island. There is evidence indicating that, at some point in the early eleventh century—perhaps in the 1020s–1030s—a mint may have developed and functioned on Mann. Coins that appear to have been minted on the island roughly coincide with Echmarcach's rule. These coins are very similar to those produced in Dublin, and may be evidence that Echmarcach attempted to harmonise the coinage utilised within his realm. The production of coins on Mann appears to be evidence of a sophisticated economy in the Isles. In fact, the wealth and sophistication of commerce in Echmarcach's realm could in part explain why the constant struggle for control of Dublin and the Isles was so bitter, and could account for Þórfinnr's apparent presence in the region. During his second reign, Echmarcach may have been involved in military activities in Wales with Gruffudd ap Rhydderch. For instance in the year 1049, English and Welsh sources record that Norse-Gaelic forces were utilised by Gruffudd ap Rhydderch against his Welsh rivals and English neighbours. Specifically, the Anglo-Saxon Chronicle, the thirteenth- and fourteenth-century Brut y Tywysogyon, and the twelfth-century Chronicon ex chronicis record that a Norse-Gaelic fleet sailed up the River Usk, and ravaged the surrounding region. These sources further reveal that Gruffudd ap Rhydderch and his Norse-Gaelic allies later surprised and routed the English forces of Ealdred, Bishop of Worcester. Since Echmarcach's extensive imperium appears to have spanned the Irish Sea region, it is possible that he was regarded as a threat by Siward, Earl of Northumbria. There is reason to suspect that, by the mid eleventh century, this Anglo-Danish magnate extended his authority into what had previously been the Kingdom of Strathclyde. Echmarcach's apparent descent from the Uí Ímair—a dynasty that once reigned over York as kings—combined with Echmarcach's accumulation of power after Knútr's demise, could well have been a cause of concern to the York-based earl. Such unease could partly account for Siward's extension of power into the Solway region, a sphere of insecure territory which may have been