Phra Nakhon Si Ayutthaya or Ayutthaya Province was the capital of Thailand. There were some evidences proved that it was the city that was situated on the plain of Chao Phraya River since Buddhist era 16-18, for example, the sign of city, ancient remains, antiques, the annals, as well as the stone inscription, which is the contemporary evidence that most coincide with the incident (Ayothaya or Ayutthaya Kingdom was situated on the east of Ayutthaya isle). It was one of the prosperous cities in terms of politics, administration, and culture. In regard to administration, three administrative laws were enforced: Comprehensive Law, Slavery Law, Law of Obligation. Ramathibodi I (Uthong) established Ayutthaya as the capital city in 1350 and it had been the center of Siam for 417 years. During those years, there were 33 Kings from 5 different dynasties:
1. Uthong dynasty 2. Suphannaphum dynasty
3. Sukhothai dynasty 4. Prasat Thong dynasty
5. Ban Phlu Luang dynasty
Ayutthaya lost independence to Myanmar twice. The first loss of independence was in 1569 and King Naresuan retrieved independence in 1584. The second loss of independence was in 1767 which King Taksin retrieved independence in the same year. Thon Buri was established to be the capital and people from Ayutthaya were relocated to Thon Buri to build the stable city. However, there were some people who remained settle in Ayutthaya and some who escaped to the forest came back to live around the city. They assembled and established themselves as the province called "Krung Kao" or The Old City.

Phra Phutthayotfa Chulalok or Rama l founded Krung Kao as a province as same as in Thon Buri period. Later, Chulalongkorn or Rama V initiated the administrative reform for both central and provincial region. In regard to provincial administration, he applied the "Tesaphiban Administrative System" (local government) by assembling the 3-4 neighboring cities to form as a "Monthon" (administrative subdivisions) that governed by a royal commissioner. In 1895, he establishd Monthon Krung Kao that comprised of cities i.e. Krung Kao or Ayutthaya, Ang Thong, Saraburi, Lop Buri, Phrom Buri, In Buri, and Sing Buri. Afterwards, he merged In Buri and Phrom Buri with Sing Buri and established Monthon administrative office. In 1926, Monthon Krung kao had changed to Monthon Ayutthaya. As a result, Ayutthaya became a center of administration. Creation of public utilities had great impact on the development of Ayutthaya. After the cancellation of Tesaphiban administrative system, after the administrative reform in 1932, Ayutthaya became Phra Nakhon Si Ayutthaya Province until present.
During the period that Field Marshal Plaek Pibulsongkram was the Prime Minister, there was the policy for reconstruction of ancient remains in Ayutthaya to celebrate the 25th Buddhist century anniversary. Moreover, in 1955, the Prime Minister of Myanmar visited Thailand and granted 200,000 baht to reconstruct temples and Phra Mongkhon Bophit, which was the beginning of ancient remains reconstruction in Ayutthaya. Later, Fine Arts Department was the main agency to process the reconstruction. Afterwards, United Nations Educational, Scientific and Cultural Organization or UNESCO resolved to register Phra Nakhon Si Ayutthaya, covered Ayutthaya Historical Park area, as the "World Heritage" on 13 December 1991.
Provincial Plant of Phra Nakhon Si Ayutthaya Province
The Cordia dichotoma tree is in Boraginaceae specie. It is the middle size plant, approximately 60 feet height. The stem looks like the grey and and brown strong wooden tube with ½ inch bark with the crack along the stem. The leaf is 5 inches long, 3 inches wide in oval shape. The bottom of the leaf is like a heart shape. Flower is white color and the fruit is green when it is ripe. The Cordia dichotoma tree is normally found in the general forest in the north, central, and the northeast of Thailand. When King U-Thong relocated the city to Nong Sano District, he discovered the conch shell under the Cordia dichotoma tree, so it finally became the provincial plant.

Provincial Flower of Phra Nakhon Si Ayutthaya Province
The provincial flower is Sesbania aculeate or Dok Sano, which is in Leguminosae specie. It is softwood shrub, with fleshy stem that normally found in the streams, rivers, and swamps in central of Thailand. The flower is yellow in bunch looks like gold, which is eatable. In 1350, King U-Thong established the new city at Wiang Lek District and decided to choose the location for the palace. He realized that Nong Sano District was the most suitable location because there were lot of Sano tress with beautiful flowers like the gold. Therefore, Dok Sano is the provincial flower of Phra Nakhon Si Ayutthaya.

Provincial Animal of Phra Nakhon Si Ayutthaya Province
Macrobrachium rosenbergii or Giant Malaysian prawn
In 1980, Queen Sirikit founded Bangsai Arts and Crafts Center on bank of the Chao Phraya River, in T. Chang yai, A. Bang Sai, Phra Nakhon Si Ayutthaya Province, and royally opened this center on 7 December 1984, as well as released the first set of prawn babies in front of the center and constantly release to present time. When Queen Sirikit visited Siriyalai Palace, she released a million prawn babies at the front of the palace.
Geography
Phra Nakhon Si Ayutthaya Province is situated in the flat plain in the central of Thailand. It is 75 kilometers far from Bangkok on Asian Highway, 72 kilometers by train, and 103 kilometers by sea route. It is covering 2, 556.64 km2 or 1, 597, 900 rai. It is the 63rd largest province in Thailand and the 11th of the central provinces. The topography is the flood-plain land. Most of land are paddy fields, no mountain range or forest. There are 4 rivers flow through i.e. Chao Phraya River, Pa Sak River, Lop Buri River, and Noi River, which the total length is 200 kilometers. There are 1, 254 course of canals connected to the rivers throughout the area.
Location and Territory
Phra Nakhon Si Ayutthaya Province is connected to the following neighboring provinces:
- Ang Thong and Lopburi to the north
- Nakhorn Pathom, Nonthaburi, and Prathum Thani to the south
- Saraburi to the east
- Suphanburi to the west