This hybrid map shows the former location of St. Patrick's Cross and The Pool of Liverpool superimposed on a 1920s map of Liverpool City Centre
Is there a connection between St. Patrick's Cross and the Irish Vikings who settled on Merseyside in the 10th Century? There isn't any archaeological or historical evidence for such a link. The Vikings don't appear to have had a significant presence in central Liverpool. Could the cross still have had Irish or Celtic origins? Irish and Welsh Celtic missionaries were active in the Dark Ages trying to revive the old Roman communities and convert the pagans after the fall of the Roman Empire. These missionaries did bring Celtic Christianity to parts of England so their involvement is a possibility.
St. Patrick's Cross was more likely set up as a "Way Marker" cross after the foundation of the borough of Liverpool. It was located on the fringes of the town and it was known to have been a landmark that was mentioned in relation to a route to other places. Its construction appears to have been functional rather than commemorative. The cross was on a route out of town taken by people going to the parish church at Walton. The church at Walton has very ancient roots and was Liverpool's parish church until 1699.
The design of the cross may have led people to believe that it was Irish or associated with St. Patrick. It's possible that Irish or Manx masons living in Liverpool c13th to 15th century were commissioned to construct the cross. Unfortunately there are no surviving records from this period. It's interesting that there was a place of burial and habitation for plague victims on the outskirts of the town called "Sick Man's Lane". Picton identifies the modern location as Addison Street. St. Patrick's Cross would have been on the funeral path of processions going between the town and "Sick Man's Lane".
Over time the original function of the cross was lost and people from Ireland and the Isle of Man may have contributed to the folklore concerning its possible origins. The visit of St. Patrick to Liverpool was probably suggested as the reason why an Irish looking cross was in Liverpool. During the English Civil War Liverpool endured three sieges and the cross may have suffered some damage during this turbulent time. The remains of the cross might have been removed while improvements were carried out to the road in Georgian times.