The 19th-century Ottoman Tanzimat reforms greatly transformed Eastern Catholic communities’ political position and internal organisation. Political recognition widened the horizons of these communities and led to a reimagination of the borders of communal belonging within the empire and beyond. Eastern Catholics attempted to carve out a space of autonomy between their orthodox counterparts and Rome and faced internal challenges to the institutionalisation of their Church, such as the blurry border between family and ecclesiastical property, and conflicting claims of authority, jurisdiction, and representation. These conflicts resonated among diaspora communities in Paris, Livorno or Calcutta. We will explore these developments by analysing three conflicts that divided Greek Catholics in the Patriarchate of Antioch in the 19th century: conflicting claims over a bishop’s sleeves’ buttons, the adoption of the Gregorian calendar and a diplomatic struggle over the shape of the clergy’s hats.