'ruler' is an appropriate word to use in written English.
You can use it when referring to a person in charge, or a device (such as a ruler) for measuring and drawing straight lines. For example, "The ruler was used to measure the length of the table."
Charles was a classic Liberal home ruler within the UK.
However, Abdullah was perhaps the first Saudi ruler to seek a new legitimacy, this time emanating from serving the people rather than simply applying divine law.
Qatar's record at the security council stems partly from the character of its ruler, Sheikh Hamad bin Khalifa al-Thani, and partly from the fact that both America and Britain will start importing liquefied natural gas (LNG) by tankers from Qatar in 2008.
Related: Muhammadu Buhari: reformed dictator returns to power in democratic Nigeria John Oloyede, a legal expert and pundit on Nigeria's Channels television, said: "He is the first Nigerian ruler, head of state, to congratulate somebody who is going to take over from him.
Equatorial Guinea stepped in to save the tournament – a personal decision by Africa's longest-serving ruler, Teodoro Obiang, who has ruled the tiny, Spanish-speaking nation since 1979.
When the city was first built, its mountainous backdrop provided natural protection against attack by the enemies of the then colonial ruler, Spain.
What better way for a ruler to claim legitimacy than to rule from this proto-capital?
However, last Monday's action was the latest in a string of independent decisions taken by Sheikh Hamad since he became the ruler in a bloodless coup against his father in 1995.
More than 13,000 people have died in the conflict and the main opposition candidate, the former military ruler Muhammadu Buhari, has campaigned hard on the government's security record.
In the days leading up to his arrival, outgoing ministry spokesman Abbas Iraqchi regularly dismissed the suggestion that the Omani ruler was carrying a message for Tehran as "spinning tales... attempts by the foreign media to foul the positive climate that has appeared from the change of government.
With 32 of Nigeria's 36 states, plus the capital, declaring results, former military ruler Muhammadu Buhari was leading the incumbent, Goodluck Jonathan, by 2.9m votes, according to official results.
