His antipathy to militant Islam may also have been fed by the reports of atrocities carried out by Turks in Bulgaria in 1876.
I am indebted to the biography of the great man by Roy Jenkins for the quotations. This book also shows how easy it was for people (provided they had the wherewithal) to move about Europe in the latter half of the eighteenth century. Gladstone spent a great deal of his time on the continent. UKIP would clearly not approve.