 Complete the following phrase:  When her father died in February 1952, Elizabeth  then 25 years old  became head of the Commonwealth and queen regt of seven independent Commonwealth countries: the United Kingdom, Canada, Australia, New Zealand, South Africa, Pakistan, and Ceylon. She has reigned as a constitutional monarch through major political changes, such as the Troubles, devolution in the United Kingdom, accession of the United Kingdom to the European Communities, Brexit, Canadian patriation, and the decolonisation of Africa. Between 1956 and 1992, the number of her realms varied as territories gained independence, and as realms, including South Africa, Pakistan, and Ceylon renamed Sri Lanka, became republics. Her many historic visits and meetings include a state visit to the Republic of Ireland and visits to or from five popes. Significant events have included her 