Researching the history of Tynte's Castle has brought to light that the building has borne witness in one form or another to the major events and developments of Youghal specifically and Ireland generally since its construction in the 15th century. Apart from limited antiquarian interest at the turn of the century there has been little historical research carried out on Tynte's Castle. What is known is that the castle was erected in the 15th century as a fortified residence of the Anglo-Norman Walshe family. It remained as part of the estate of this merchant family until they forfeited it in 1584 and acquired by the town Corporation. The Walshe's sided with the Earl of Desmond during his unsuccessful rebellion against English power in Munster in the mid 16th century. Subsequently the Castle passed to the Corporation of Youghal; who in turn leased it to Robert Tynte.

Robert Tynte
Robert Tynte was the fifth son of Edmund Tynte of Wraxhall, Somerset, England. He arrived in Ireland some time in the late 16th century as part of a group of entrepreneurial soldiers and administrators known as 'adventurers'. These men were arriving in Ireland at a time when English Royal administration was reasserting its power in Munster following the Desmond Rebellion. A great sea change was taking place with the replacement of the Gaelic lordship economy with a market style English economy. Men such as Tynte, along with their counterparts in the Americas, were taking England's fledging steps towards creating an empire. Tynte worked as a soldier and administrator for the Office of the Sheriff of Cork and became acquainted with Richard Boyle, Earl of Cork. Boyle is closely associated with the history of Youghal, purchasing the town as part of his acquisition of the Munster estate of Sir Walter Raleigh. Richard Boyle had a substantial residence, known today as 'The College', close to St. Mary's Collegiate Church. Boyle occupied the office of Sheriff from 1625 to 26. It would appear that Tynte operated under the patronage of Boyle for some time; he is mentioned in several of Boyle's papers and letters.

In 1612 Tynte married Elizabeth Boyle, widow of the poet Edmund Spenser. Local tradition holds that Spenser wrote the final verses of his poem the Faerie Queene in a window seat of Myrtle Grove,

 
a substantial fortified house close to Boyle's residence in the College of Youghal. Both of these buildings are buildings are within 200 meters of Tynte's Castle.

Tynte acquired a permanent lease of Walshe's castle from the corporation of Youghal some time after the forfeiture of the building in 1584. By securing the castle in Youghal Tynte was able to gain a firm foothold in the new economic infrastructure that was being promoted by the English administration. The castle provided a secure storage facility and safe accommodation in the town. The new economic landscape was based on exploitation of the land for profitable returns. In order to realize these returns as profit, trade and export through the towns again became important. Port towns, especially those of Cork, Kinsale and Youghal developed rapidly in the later 16th and early 17th centuries to serve the needs of an ever-expanding agricultural hinterland. From 4378 stones in 1616 the export of raw wool from Youghal rose to 15, 716 in 1625.

It is not known if and for how long Robert Tynte was in residence in the castle; he also acquired lands in the Barony of Imokilly, amongst these was the rural tower house at Ballycrenane, Co. Cork. It is probable that he used his castle in Youghal for trading produce from his land holdings, whilst the residential space above would have provided apartments in town. Undoubtedly, Robert Tynte and his descendants used Tynte's Castle to exploit the opportunities for profit offered by events in Ireland of the 17th century. Robert Tynte died in 1663 and is buried in Kilcredan, near Castlemartyr, Co Cork.

After Robert's death the castle appears to have remained part of his families estate. An unsuccessful attempt to burn the castle was made in 1689 while it was being used as a place of confinement for old Cromwellian supporters during the reign of James II. Little is known of the castles role during the Cromwellian occupation of the town; a substantial structure such as it would have been important to any occuping force. Youghal sided with Parliementarians when Oliver Cromwell arrived the gates after he had sacked the town of Dungarvan, 20 miles to the east. Cromwell wintered his army in Youghal during the winter of 1651. Little else is currently known of the history of the castle until its conversion to a grain store. The castle was recorded as being one of the locations that delimits judicial boundaries within the town often mentioned in 17th century ordinances of the Corporation.

At some time during the 19th century, possibly earlier, the building was heavily altered during conversion into a dry goods store. The late 18th and early 19th centuries was a very prosperous time for Youghal. The beginnings of Empire and the Napoleonic Wars generated a boom in Irish exports. The castle was readily convertible to suit the need of storage, a purpose it fulfilled since its construction. The structure retains some interesting wooden features from this phase of activity that was concerned with the drying of grain. Apparently this period was short lived, as from the description of it in the 1850's as being in a distressed state. The castle was acquired by the present owners in the 1950's and has remained unaltered since.