The Palatines were Lutheran refugees who fled from the Rhenish Palatinate of Germany due to an invasion by the French. They came to the area in 1708-09 under the patronage of Lord Southwell. Approximately twelve hundred Palatines came to settle in the area and their new ideas in farming were a large contributing factor to the development of the town. Rathkeale was also a major market town for the area and held seven fairs throughout the year.
The name Rathkeale comes from the Irish 'Ráth Caola' and it is believed to be derived from Ráth gCaeli, which means "the fort of the Caeli" or "the Rath of Caola". The Caeli were a Celtic tribe who came from this area of Limerick. The parish of Rathkeale is made up of the old parishes of Rathnasaire and Kilcoleman.
The Earls of Desmond used Rathkeale as a base. Castle Matrix was the principal stronghold of the Desmonds in the area and was built in or around 1410 by the Fitzgeralds of Desmond. In October 1580, two famous visitors came to stay at Castle Matrix. They were the poets Edmund Spenser and Walter Raleigh.
Sir Nicholas Malby burned the town of Rathkeale in 1579 after he defeated the forces of John, Earl of Desmond. John and his forces fled to Rathkeale from Manister where Malby had earlier defeated the Irish.
Captain Walter Raleigh ambushed the Irish, who were about to plunder what was left of the English camp once the troops had left. He received the freedom of the town in 1580, as a reward. Raleigh also repaired the castles at Rathkeale (Desmond's) and Matrix. The lands of the Munster Geraldines were in the main divided up amongst Spenser, Raleigh and Edmund Southwell. Raleigh gave some 'Virginia Tubers' as a present to Southwell. Southwell planted the tubers in the land around Castle Matrix and, in 1610, the crop was distributed throughout the province of Munster.
In 1654 Cromwell fixed the town as the place for the election of the counties of Limerick, Cork and Kerry for his parliament. However, Cromwell changed his mind on this point when the town refused to supply his army with sufficient provisions of food.
In the past church appointments were sometimes challenged by the local gentry. In 1748 the parish priest Fr. James Moore died. Henry Southwell lead opposition to the appointment of a number of priests by Dr. Lacy and finally the position of parish priest was successfully held by David Bourke who lived in the parish until his death in 1762.
In 1846 a hoard of coin was discovered in Rathkeale. These coins were minted during the reign of Edward III (1327-1377). It is believed that the coins may have been part of the spoils of the O'Briens victory at Monasteranenagh in 1370.