THOMSON / Elizabeth  Ancestry
Alexander was born in Edinburgh - Elizabeth possibly in Market Drayton (1851 census), though not backed up by 1841 census entry. Marriage records from 1812 for Market Drayton have been lost in a past fire, so Elizabeth's origins are unknown.

Two Alexander Thomsons were baptised in Edinburgh in 1785 - one to James/Lillias Scott, the other to Alexander/Flora Murray. However, Alexander/Flora had a second Alexander baptised in 1789, so presumably their first Alexander had died. This would suggest James/Lillias were Alexander's parents which seems likely given that Alexander & Elizabeth's eldest son was called James (b.1816).
The 1785 date is based on Alexander's age being given as 65 in the 1851 census.

It should be noted that several other Alexander Thomson's were born in Edinburgh in 1781/2. Interestingly, Alexander & Elizabeth's son Charles (b.1822) has a visitor called Alexander Thomson staying with the family in 1851 - he was also from Edinburgh, and his age appears to be given as 68, indicating born ca. 1783. Could he have been one of these other Alexander's, and are they in any way related ??