Stratmarghel c.1170, 1322, St(ra)dmarchell 1183, estrat marchell 1191, Stradmarhel 1198, Stratmarchell 1200, Strat Marchell 1322, 1584. Ystrad Marchel 1330, Strattemarcelle 1333, Ystrad Marghel 1341, ystrat marchell 1197 (14g.), Strate Marcelle Abbey 1536-9, (maenol) Streatmarshall 1640
Scedstradmarchel 1271, Swythstradmarcell, Soyrstradmarghel 1278, Southstradmerghell 1421-2, Soothestrademerghele, c. 1423-32, Suthstradmarghel 1554

Welsh Ystrad as in Ystradelfedan, etc. with a well-evidenced personal name Marchell (from Latin Marcellus), reputedly a saint of the 5th c, dedicated at Capel Marchell ( Llanrwst) and Llanfarchell (= Denbigh church). Strata Marcella is simply a latinisation and Marchell has taken on the appearance of a female personal name to 'agree' with Strata. There is also a river name Marchell (Llanstephan) Radnorshire found as Marchell 1682 and in the farm name Llanmarchell 1832. Ystrad Marchell and Strata Marcella refer to the Cistercian monastery here otherwise called Pool (especially before about 1313): Pola 1263,1271, Poli 1278, Strata Marcella alias Pola 1496, a name taken, of course, from Pool or Welshpool. Swydd Ystrad Marchell was one of the three swyddi of Y Tair Swydd.