The recently announced decision by the Office of Public Works to commission an official portrait of former taoiseach Brian Cowen – after a long delay – is a timely reminder of an important artistic tradition. Countries worldwide have schemes to ensure that heads of state and government are recorded on canvas for posterity.

The best-known subject is Britain's Queen Elizabeth II who, according to the National Portrait Gallery in London, is "the most portrayed individual in history" and "associated with 918 portraits" – the most recent a portrait by Northern Ireland artist Colin Davidson that was unveiled late last year.

In the United States, every president since the first, George Washington, has had his portrait painted. Washintgon's portrait was painted by an artist called Gilbert Stuart and is still used on one-dollar notes. The US presidential portrait was the theme of a major photographic work of art in 2008 by the American artist Jonathan Horowitz. Titled Obama '08, it consists of digital photographs of the painted portraits of the previous incumbents plus a photograph of Obama.

Edition of three

Horowitz made the piece in an edition of three, one of which sold at a Christie’s auction in New York late last year for $223,500. According to Christie’s, the “installation” piece had been assembled before the result of the November 2008 election, when 42 “portraits hung in a line on the wall, organised chronologically from George Washington to

George W Bush

, while a portrait of

Barack Obama

[a campaign photograph and not a photograph of a painting] – then still yet to be elected – leaned against the wall, poised to be hung next in the line depending on the outcome of the election”.

Christie's said: "Horowitz conceived the installation surrounding Obama '08 as a space to watch the media coverage of the election. Two oversized television screens hung back-to-back, each live-streaming CNN and its conservative counterpart, Fox News. The artist-designed display emphasised the polarisation of partisanship by carpeting the room half in red and half in blue. On election day, Horowitz hosted a party in the installation where an all-American feast of apple pie, veggie burgers (Horowitz is a vegan) and beer was served to the attending audience. Upon the announcement that Obama had won, a cascade of red, white and blue balloons were released from the net that held them to the ceiling and his portrait was hung on the wall in a performative gesture. Had John McCain, the Republican contender that year, won, the balloons would have been left to deflate and Obama's portrait would have remained unhung on the floor; no corresponding portrait of McCain would have replaced it."

How Horowitz responded to the election of Obama’s successor can be imagined.

Reproduction

According to a catalogue note for

Obama ’08

, “each portrait in the suite is a photographic reproduction of a painted portrait of the president, cropped so that scale equalised. Often made at the conclusion of the president’s tenure, the portraits thus present a range of styles and fashions. For example, John F Kennedy’s portrait depicts the former president with his head downturned to connote his untimely death. Some portraits of presidents have been annotated with the constitutional amendments passed during their tenure that granted groups of people the right to vote.”

Sharp-eyed readers will note that the picture contains the images of 43 presidents and one blank space. But Obama was America's 44th president and Donald J Trump will be the 45th. So what's going on?

In response to a query from The Irish Times, a Christie's spokeswoman in New York, initially "stumped" by the question, explained the anomaly: "There have been 43 individuals sworn into office as president of the United States, but technically there have been 44 presidencies. This discrepancy is due to the fact that Grover Cleveland served two non-consecutive terms, and was counted chronologically as both the 22nd and 24th president. Therefore, Trump will be the 44th person to serve as US president (and the 44th portrait) . . . but he will serve as the 45th president."