Regional and temporal patterns in brooch use in Britannia are studied, confirming and challenging ‘received wisdoms’ about ‘regionality’. The complexity of the ‘Fibula Event Horizon’ is brought into sharp focus; a similarly complex and unexplained ‘Fibula Abandonment Horizon’ is also clearly demonstrated. Conclusions are insensitive to assumptions about use-life. Detailed analysis for the family of trumpet brooches casts light on hitherto unappreciated features of ‘regionality’. Comparison with continental data suggests the British temporal patterns may be reflecting a wider north-western province pattern. Under-studied aspects of bias in metal-detected finds and their implications for studies of this kind are noted. The Supplementary Material available online (http://journals.cambridge.org/bri) contains tabular information on the data used in the study and additional analyses that support some of the assertions made in the main text.
