Following the arrival of the Normans in Ireland in 1169, Henry II, gave a vast tract of land to one of his retainers, Hugh De Lacy. This land stretched from Dublin to the Shannon. De Lacy in turn granted the lands of Castleknock (Cnucha) and the surrounding district by charter to his liegeman, Hugh Tyrrel. His grant of land included what is now called the Pheonix Park, in addition to Clonsilla and Mulhuddart. Tyrrel in 1173 began fortification of Cnucha.

In 1299, an inquisition into the Estate of Hugh Tyrrel, the fifth baron who had died, showed that his Estate at Castleknock was something in the region of 7000 acres. Before the end of the 13th century, various families had settled in the district and their names were well know in the district, Abbot, Balnchard, Keppock, Luttrell, Pilate, (Pellet) and Dueswell (Diswel).

The Luttrells were a Norman family who first came to Ireland in 1204. At that time, Geoffrey Luttrell was granted the cattle and manor of Luttrellstown by King John in reward for services.

Richard Tyrrel, the sixth baron of Castleknock took over in 1299. His period of control was full of incident including his involvement in a State Trial. It appears that a falcon owned by the Chief Justice of Ireland escaped and flew to Castleknock. Richard kept the bird even though he knew whose it was, and that a reward was offered for its recovery. He eventually escaped conviction by handing the bird back to its owner.

Robert Tyrrel (the eighth and last baron of Castleknock), his wife and their son and heir died in the plague of 1370. With the demise of the Tyrrel line the estate was divided. 

In former years the area was noted for its wild life. Scald Woods, the great wood of Blanchardstown, which was a favourite place for hunting wolves. In 1652, the wolves became so numerous that the government of the day ordered a public hunt of these animals. The assembled inhabitants of the Barony were ordered to join to destroy 'the wolves lying in the wood of the ward'.

In earlier times the Phoenix Park formed part of the lands of the Earl of Stafford. On of the past times in vogue was the flying of hawks after blackbirds which attracted as many as two hundred thousand spectators to the park.

The name, “Westmanstown” is first mentioned in records in 1821. It is believed to be a corruption of the name “Waspayle”, a Norman family who were recorded in the area in the 16th century.

The Kestrel, which can be easily identified on the Westmanstown symbol, is a member of the falcon family. It is readily identified hovering as though suspended for an invisible line. The male is beautifully marked with a blue-grey and white tip, and red-brown upper parts, spotted with black. These birds are evident around the grounds of the club.