Sven Meeder and Roy Flechner introduce their collection of essays with a summary of historiography on the impact of the Irish on Continental Europe that is notably clear. They organise their survey by periods, themes, and the nationalist or religious agendas driving scholarship, and highlight key controversies. Christopher Loveluck and Aidan O’Sullivan’s chapter on archaeological evidence for travel, transport, and communication covers a large timespan, c. 400–1100, and is necessarily general. They focus on the early part of the period, synthesising Ewan Campbell’s work and noting critiques of it, and gathering together evidence for contact with Byzantium. The authors are careful to address evidence from western Britain as well as Ireland where relevant. They argue for links between trade routes and religious travel by individuals, for example linking the salt trade to western Francia and the ‘sacred routeway’ from Ireland to Rome, which passed down the Loire valley to Tours and on. The section on the Viking period 850–1100 is brief and focuses on trade to Islamic Iberia.