Manchán of Lemanaghan was an early Irish saint and poet who lived during the 7th century. As the patron of Lemanaghan in County Offaly, he established a monastery there around 645 AD after receiving land from St. Ciarán. Known for his wisdom and deep knowledge of scripture, he was also a writer of Gaelic poetry. He died in 664 during an outbreak of the yellow plague, which is recorded in Irish annals as a period of significant mortality.