slate quarrying began in the hills above tywyn in the 1830s. although many small quarries and test levels were established, only one major quarry was developed in the region. it was at bryn eglwys, north east of the town. underground working began in the early 1840s. by 1847 the quarry was being worked by local landowner john pughe. the finished slates were sent by packhorse to the wharf at pennal. they were then transferred to boats for a river trip to aberdyfi (also known as aberdovey). finally they were loaded into seagoing vessels. this was a complex and expensive transportation arrangement which limited the quarry's output. in 1861 the outbreak of the american civil war cut off supplies of cotton to the mills of the north west of england. as a result a number of prosperous mill owners looked for new business opportunities to diversify their interests. one such owner was william mcconnel of lancashire. in 1859 he purchased a house near dolgellau, north of tywyn. in january 1864, mcconnel formed the aberdovey slate company. the company leased the land including bryn eglwys from the landowner, lewis morris of machynlleth.