Dafydd ab Ieuan (c. 1350 – 1422/23[1]), better known by his English name David Holbache, was a Welsh politician, best known for founding Oswestry School in 1407.

[2] Pentrehylin means 'Helyin's village' in English and is named for Holbache's ancestor Heilin ap Trahaearn ab Iddon.

Heilin ap Trahaearn claimed descent from Tudur "Trefor" ab Ynyr, a 10th-century lord of Maelor Cantref and a founder of one of the Fifteen Tribes of Wales.

[1] He likely adopted the surname of Holbache to assist his assimilation into the English-controlled systems of governance, which limited opportunities and privileges for Welshmen.

Due to poor record keeping, little written documentation survives for the school up until relatively recent times.