The first reference to Erghams in relation to Preston comes in 1373 when Ralph de Erghum was listed as warden of St Mary Magdalen’s Hospital in the town.  In 1374 he was appointed Vicar of Preston; according to one source, he appears to have delegated the responsibility as shortly afterwards he was appointed Bishop of Salisbury.  The locative surname ‘de Ergham’ is generally taken to stem from the parish of Argam or Ergam, near Bridlington in East Yorkshire.  Another possibility, suggested by Abram, is a Lancashire origin. He notes that in the time of Edward I, towards the end of the 12th century Arkholme in Melling Parish was spelled Erghum. 
Abram’s suggestion is strongly supported by Alan Crosby’s article on surname evidence for migration to Preston at this period:
A very distinctive feature is the group of names in the middle Lune valley, including Arkholme, Cawood, Wennington and Leek. This at ﬁrst sight appears to be anomalous, since there are no names at all from the intervening area, around Garstang, Lancaster and Halton. A possible explanation is provided by the surname de Ergham or de Argham (and other variant spellings), which is derived from the township of Arkholme. The Ergham family was arguably the most important in late fourteenth century Preston …
… It is possible that the prestige of this family, and its inﬂuence in Preston, exerted a powerful effect among friends, neighbours and lesser mortals in their home territory of the middle Lune, and so encouraged movement from their part of North Lancashire down to Preston. Migration for such speciﬁc ‘personal’ motives is well-attested in later centuries, and there is no reason to suppose that it might not have taken place in fourteenth-century Lancashire. 
For more on the Preston Guild and its rolls see the two Abram books and Fishwick’s history of the town in the Preston History Library.
A John de Ergham was listed as an in burgess on the 1397 guild roll, along with his son, Adam.  This strongly suggests that John was established in the town at the time of the previous guild (date unknown but given the custom of the guild possibly in the late 1370s). The 1397 guild roll also includes William de Ergham as mayor and fined burgess, as well as his sons Robert, Geoffrey and William. The fact that he is described as a fined burgess, that is, he was sponsored for burgess status by two other burgesses and paid an entry fine, should mean that he was not a burgess at the time of the previous guild and neither was his father and suggests that he became established in the town after that guild.
A footnote in Alan Crosby’s article raises a problem with this account of William’s arrival in Preston:
A. B. Emden, A Biographical Register of the University of Oxford to AD 1500, vol. 1 (1957), states (pp. 644-5) that Ralph [the later bishop of Salisbury] was the son of William and Agnes Ergum of Preston. He was ordained in 1362 and is likely to have been born c. 1342, so that William, who ﬁrst became mayor of Preston in 1388, would have been of the right age to be his brother. 
If William and Agnes were living in Preston, then the husband should have been a burgess of the town, which should have conferred burgess status by right on William the mayor, if he was indeed the son of William and Agnes. In which case, why would he have been listed as a fined burgess on the 1397 roll?
Henry Fishwick includes William de Ergham in his list of the town’s mayors in 1388, 1396-97, 1402, 1408, 1413, 1416-19 and 1425. Alan Crosby notes, ‘William de Ergham may also have been mayor in some of the other years during this period for which all record of the mayoral name is lost: even so his record of ten mayoral terms remains unequalled in Preston’s history.’ 
Fishwick adds that Patten House in Church Street was built on the site of ‘Ergham’s Manor House’, but gives no source. 
An indication of William de Ergham’s prominence in the town is given by the fact that he was guild mayor at the 1397 guild. Regulations applying to the guild at this time would seem to preclude burgesses who were not in the previous guild roll from holding office; this should have debarred William and other fined burgesses from office but clearly did not, indicating that the guild regulations were either not routinely enforced or that William and the other fined burgesses gaining office had sufficient authority to negate this particular regulation.  William is listed as the proposer of new burgesses to the guild rolls 19 times. In 17 of these entries he is the first proposer, more than any other burgess; a fact that might be a status indicator. The rapid rise to prominence of William de Ergham in his adopted town would appear to parallel that of John Horrocks, 400 years later.
The Ergham family could have continued living in Preston until well into the 16th century. According to Fishwick, citing Kuerden, a W. Ergham was a steward at the 1500 guild.  In 1540 Isabella Ergham married Henry Preston and a William Erram gent appears on the 1582 guild roll; Henry Preston’s son Henry is recorded in his post mortem inquisition of 1601 as having bought Aram House from William Aram, gent, who Fishwick identifies as William Argham, son of Richard Argham, who both appear on the 1562 guild roll.  The progression from de Erghum in 1373 to Aram in 1601 by way of Argham and Erram seems quite likely. This would make Aram House a more probable site of ‘Ergham’s Manor House’ than Fishwick’s suggestion of Patten House.
Aram House would presumably have abutted the Aram’s Backside that was later renamed Molyneux Square. A deed of 1439 refers to ‘the Hopgreave towards Erghum sike’. Another deed of 1522 refers to ‘a close called … Erghom Hey’. (de Hoghton deeds: 327 and 339)
 British History Online, ‘Hospitals – St Mary Magdalen, Preston’, A History of the County of Lancaster: Volume 2, 22 June 2003, http://www.british-history.ac.uk/report.aspx?compid=38360#n21.
 Henry Fishwick, The History of the Parish of Preston in Amounderness in the County of Lancaster (Rochdale: Clegg, n.d.), 176.
 British History Online, ‘Areley – Arncott’, A Topographical Dictionary of England, 22 June 2003, http://www.british-history.ac.uk/report.aspx?compid=50759#s3.
 W. A. Abram, Memorials of the Preston Guilds (Preston: Preston Guardian, 1882), Page not numbered, in corrections at front of book.
 Alan G. Crosby, ‘Migration to Preston in the Fourteenth Century: The Evidence of Surnames’, The Lancashire Local Historian 8 (1993): 14–15.
 W. A. Abram, The Rolls of Burgesses at the Guilds Merchant of Preston, vol. ix (Record Soc. of Lancs. & Ches, 1884). Guild Roll references, unless otherwise stated, are taken from this source.
 Crosby, ‘Migration’, 15 fn. 2.
 Crosby, 15 fn. 1.
 Fishwick, The History of the Parish of Preston in Amounderness in the County of Lancaster, 75–76.
 Alan Crosby, The History of Preston Guild: England’s Greatest Carnival, 2nd ed. (Preston: Carnegie Publishing, 2012), 16.
 Fishwick, The History of the Parish of Preston in Amounderness in the County of Lancaster, 37.
 Fishwick, 218–19.