The Pig Memorial was built in 1913 to commemorate the 50th birthday of Queen Saovabha Phongsri (born Friday duen ai ram 7 khum (Waning of the 7th night of the 1st Lunar Month, Year of the Pig, or 1 January 1863). It is located at the base of Pi Kun Bridge, which was built two years prior, to commemorate the Queen's 4th Zodiac Cycle.
The Pig Memorial is also known as Sahachart Memorial. Sahachart means "those who were born in the same year". The name references the three high-ranking officials who were born in the same year as the Queen: Prince Narisara Nuwattiwong, Phraya Pipat Kosa (Celestino Xavier) and Phraya Ratcha Songkram (Korn Hongsakul). The three erected this monument in honour of the Queen in the shape of a pig, signifying the Chinese Zodiac Year in which the Queen was born, as were the three officials. On the pedestal of the monument a blessing to the Queen is engraved and also includes the names of the commemorators.
What was special about the memorial is that it was meant to be “u-tok tan” meaning giving alms by means of giving water. In other words, the memorial was also a source of clean water for the general public. The idea behind this generosity belonged to the three commemorators. Prince Narisara Nuwattiwong, Phraya Pipat Kosa (Celestino Xavier) and Phraya Ratcha Songkram (Korn Hongsakul) wanted to give the Queen a birthday gift, but the Queen said she would not receive any gifts that year. The three officials brainstormed to find a loophole in the Queen's forbiddance, and came up with the idea that they would build a clean water supply for the people in the name of the Queen instead of giving her a gift. Many years later, the waterworks were removed and only the memorial remained.