Conservation of Ayutthaya Historic City in the past was restricted in various aspects, therefore, it was emphasized on important monuments with more distinguishable remain whereas smaller monuments, archaeological sites, historical places and monuments which were parts of urban structures had not been duely attended thus they had suffered trespasses and damages for a very long time.
Later On, when cultural heritage conservation concept was widely known, the government realized its significance and was well- prepared financially thus began survey, study, planning and preparation of conservation master plan in order to realize conservation and development and to resolve various problems which have long been accumulated.
For Ayutthaya Historic City, legal measures are used as part of the strategies in protection, safeguarding, maintenance and also is an important device for conservation management and development of Ayutthaya Historic City.
The principal law is the Act on Monuments, Antiques, Objects of Art and National Museums B.E. 2504, revised (2nd Issue) B.E. 2535 While Act on Town Planning B.E. 2518 and Act on Building Control B.E. 2522 are used as supporting laws.
The exercise of legal measures in conservation and development of Ayutthaya Historic City has rendered rather satisfactory results, however Laws and Regulations which enforced at present are not entirely correct and there remain some practical problems such as:

1. Obscurity of certain specifications and rules in different laws and regulations.
   
2. Applications of many different laws under many authorized offices causing inconvenience to both the responsible offices and the people.
   
3. The Possibly most important problem is that enforcing laws and regulations decrease the people's rights both those of governmental and private sectors to certain extent. For instance, they lose opportunities in development i.e. building and certain economic development while there is not yet effective laws or incentive schemer to compensate such losses and benefit people in conserved areas i.e. tax exemption for those whose support and cooperate in conservation, special advantages, opportunity for people in conserved areas such as privileges in employment and concessions, exemption of monument visiting fees, etc.

The above mentioned problems require revisions of laws and regulations however, very important schemes are promotion and educational programmes for local people in both legal and conservation aspects in order to formulate conservation alliance with the public. Then, local people will be the ones who impel and direct their own means of conservation instead of government sector. This may be the highest goal by means of conservation instead of government sector. This may be the highest goal by means of sustainable conservation and development, then, legal measures might not be necessary after all.

Ayutthaya, is nestled on an island in the junction of the Chao Phraya, Lopburi and Pasak rivers in lower central Thailand. The land of this region is fertile with soils suitable for rice culture. Its river systems facilitated internal and international communication and transportation, and served Ayutthaya as a commercial and trade center of Asian region and the world.
Prior to the establishment of Ayutthaya at mid 14th century, there are numbers of independent city-states locating in present Thailand, for instance, Lanna and Sukhothai in the north and Nakhon Si Thammarat in the south. During that period, political and cultural power of Khmer were superior to the area in northeast and central Thailand and was centralized at Lopburi. Historians believe that Ayutthaya had been a border town of Lopburi and located at the area east of present Ayutthaya island, known as "Muang Ayothaya".
Most of dependencies in Mainland Southeast Asia declared their independence when the Khmer Empire declined in the 13th century. Soon after that, in the year 1350, King Ramathibodi I or Phra Chao U-Thong (1350-1369), was empowered by his relative cities such as Suphanburi, Lopburi and Sanburi, to establish Ayutthaya as a new capital of central Thai.
Later On, Ayutthaya developed the country, expanded her territory and played as the great capital of Thailand for the period of 417 years. There were 33 kings from 5 dynasties ruling the country. Ayutthaya was invaded and absolutely destroyed by Burmese invaders in the year 1767, in the reign of King Ekatat(1758-1767), the last king. This caused the Thais to move further and re-established their new capital at Thonburi and steadfastly settled down at Bangkok up to present.

The Historic City of Ayutthaya, with all of its remains, is considered to be property of outstanding universal value and is listed as the World Heritage by UNESCO, on December 13, 1991 at Carthage, Tunisia, for the following reasons:

1. Ayutthaya represents a masterpiece of creative genius of perceptive selection of the location of a site to suit a complex scheme of site planning that capitalized the natural features of the typically Thai water-based settlement and culture to satisfy the demanding needs of the capital city to defend itself with the help of nature against enemy's attacks and to be blessed with an infrastructure system that would ensure its prosperity in peace time.
   
2. The city plan of Ayutthaya exerted a decisive influence on Bangkok. In fact, Bangkok in its early years was Ayutthaya's resurrection in every aspect, including the structural arrangements, even the names of places, the unique houses, boat houses, royal barges and boats, and life styles.
   
3. The Historic City of Ayutthaya, and for what it was as a capital city, is distinctive and unique, and there is no historic city anywhere in Asia or any other arts of the world of its like.
   
4. The monuments in Ayutthaya are unique and outstanding in architectural design of the region. Many structures such as chedi, prang, and prasat have the distinctive character and appearance which cannot be found alike anywhere else, through the origins were from an earlier period. The architectural design of Ayutthaya represents the continuation of architectural development irreplaceable now as a traditional Thai style.
   
5. Architecture, paintings, and art objects of Ayutthaya associated to the nominated area are unique in their style, design, craftsmanship, materials, integrity and rarity.
   

1. Ayutthaya Historical Park Area covering 1,810 rais approximately (about 715 acres) is area within the City Island registered as national monument area since B.E. 2519
   
2. Area other than that of area I within the City Island
   
3. Area outside the City Island on the East (including Ayotthaya City area)
   
4. Area outside the City Island on the West
   
5. Area outside the City Island on the North
   
6. Area outside the City Island on the South
   
7. Areas other then Area 1-6 within Ayutthaya Province
   

1. Work-Plan for Archaeological, Historical Research and Restoration of Monuments, which depends upon archaeological knowledge and preservation / restoration as the key procedures. Within this plan, the Nation Center for Restoration of Monument will be established.
   
2. Work-Plan for Development and Improvement of Infrastructure of the Historic City. Its main activities include the rehabilitation of ancient canal systems and providing more infrastructure such as electricity, water supply, telephone link, etc. among the present communities in the proposed area. All of these must be designed and constructed in harmony with a historical atmosphere of the city.
   
3. Work-Plan for Restoration and Landscape Improvement of the Monuments. The plan is to rectify all surrounding physical environments which are unsightly and not in harmony with the atmosphere of Historic City.
   
4. Work-Plan for the Development and Improvement of Residential Communities. Such communities, in fact, create much lively atmosphere to the city, but some of those lying within or blocking the scenic views of the monuments and historical sites must be relocated in such way that appropriate and orderly atmosphere could be achieved.
   
5. Work-Plan for the development of Headquarters and Personnel. This is to construct the headquarters building, to secure office facilities, to form working team adequately for every aspect to the project work.
   
6. Work-Plan for Academic and Tourism Services. The plan is to establish an information center fully equipped with documents and other media making full use of new technology.
   
7. Work-Plan for the Improvement of Socio-Economic of Local Residents. The plan's effort must be made to promote earnings through various occupation activities related to tourism, together with the promotion of local arts and crafts through the development of an art-craft village.
   
8. Work-Plan for the Relocation of Industrial Plants and Redevelopment of their terrain. Industrial plants and factories are not in accord with the atmosphere of a historic city. Some of them are located in the Rear Palace (Wang Lang) area. These must be relocated and the terrain property restored.
   

1. Constitution of the Thai Kingdom
   
2. Act on Town Planning B.E. 2518
   
3. Act on Building Control B.E. 2522
   
4. Act on Monuments, Antiques, Objects of Art and National Museums B.E. 2504, revised (2nd Issue) B.E. 2535

1. Constitution of The Thai Kingdom

Constitution of the Thai Kingdom is the highest law of the nation. It is considered the mother law which determines policy and principles as guidelines for enactment of lesser laws and regulations for each office and project as appropriate.
Substantial contents on cultural heritage specified in the Constitution are:

Chapter 3 on Rights and Freedom of the Thai Citizens: Section 46 specifies "People who group to form an original native community have their rights to conserve and revive norms, traditions, local ingenuity, arts and righteous culture of the local and nation, to participate in the management, maintenance and to benefit from natural resources and environment in a balance and sustainable means as the laws specify.
Chapter 4 on Duties of the Thai Citizens: Section 69 specifies "A person has duty to protect the country, serve the army, pay taxes, help the government, be educated, guard, protect and transmit arts and culture of the nation and local ingenuity, and conserve natural resources and environment as the laws specify.
Chapter 5 on Fundamental policy of the Government: Section 81 specifies "The government must provide education and encourage the private sector to provide education in order to establish knowledge along with morality, and to enact laws on national education, improve the education to be in accordance with economic and socia changes, to formulate knowledge and establish true conscience on politics and administration in constitutional monarchy, encourage research in arts and sciences, expedite development of science and technology for national development, develop educational profession and promote local ingenuity, arts and culture"

The contents of the above 3 chapters are intended to emphasize on transmission and conservation of culture, determination of duty and responsibility of government sector, and fights and duty of the people in both mentality and practical aspects which will obviously bring a positive result on cultural heritage. In order to make the Constitution more applicable, the government has to enact lesser laws and regulations to serve as implementation guidelines such as acts, ministerial regulations, ministerial declarations, etc.
In fact, the enactment of lesser laws and regulations as mentioned is unavoidable to have some negative effects on the people involved which the Constitution has not clearly specified this aspect. Losses of benefits, rights and advantages of the people resulted from conservation have caused the government sector to lose public alliance therefore, the implementation solely by the government has never achieved a sustainable result and consequently, successful implementation of the policy specified in the Constitution could not be completely accomplished.

2. Act on Town Planning B.E. 2518

The responsible body for enacting the Act on town Planning B.E. 2518 is the Department of Town and Country Planing, Ministry of Interior who is authorized to enact ministerial regulations to direct urban growth of certain town in a correct and appropriate direction by control of land-use, activities and scales of activity in different areas including communication networks within the city plan limit. The plan is revised every 5 years and assigned to local government or administrative body to supervise the implementation of the city plan.
This act is to be enforced in particular areas. For the areas with historical, and archaeological significance, the Fine Arts Department by the Bureau of Archaeology and National Museums who is responsible in this aspect collaborates with the Department of Town and Country Planing in specifying areas to be conserved which will be rendered with brown colour on the declared city plan.
Substantial contents are to promote activities which are supporting, agreeable and harmonize with characteristics of Thai art and culture, and those for public benefits, while prohibit dangerous or environmentally damaging activities such as industries, storage for hazardous materials, prohibited service places, etc.
The present General town planing of Ayutthaya specifies the area of monuments within Ayutthaya Historic City coveting 3 sq. kms., which is approximately 40% of the City Island (the Project area in the 1st phase) as conserved area, coloured brown. The rest of the area within the Island, about 60% is specified by other colours according to present land-use and future trends. Such specifications may cause damaging activities to the monuments and archaeological sites in the area. Besides, areas outside the City Island especially those on the east and the north are also important which require further investigation and revision of the town plan to make it more appropriate.
To conclude, the city plan is the law enacted to control urban development since B.E. 2518 supports conservation on urban level. Degree of efficiency and support on conservation that this act renders depends on:
Firstly, specification of colours for areas surrounding the conserved area (brown) should be considered how to make the areas harmonize with, and act as buffer areas to the conserved area while not conflicting with urban development trends.
Secondly, how strictly could the local administrative offices such as the municipality, the district, implement the act.

3. Act on Building Control B.E. 2522

Act on Building control in enacted to specify and control buildings to meet construction standards of strength, safety, sustenance of environment quality, and conforming with the traffic and city plan. It is under control of the Civil Department, Ministry of Interior.
Local administrative offices are the authorized supervisors of the Act and can enact further regulations and details as appropriate. In case such regulations and details are not in accordance with the main Act, they can propose it to the Ministry of Interior for considerations.
Details of control comprise the size (width, length, height, total area of building, floor area ratio), setbacks, safety systems, sanitary systems, form and other relevant details.
This act is widely adopted because is concerns mainly the necessary aspects for people's quality of living. As for aesthetic aspect, it is not much emphasized due to lack of sufficient supporting scientific criteria, also it is possible to bring about more negative effects on people.
Nevertheless, this act is very much beneficial to conservation. Enforcement of the act requires a thorough investigation and study of the area in order to the able to solve problems as mentioned in previously.
The Ayutthaya Historic City Project Office has collaborated with other offices involved in the enactment of the regulations to draft the Building Regulation for Ayutthaya City. This was proposed as a Ministerial Declaration in B.E. 2540.
The main purpose of this Building Regulation is to support the conservation and development of the Ayutthaya Historic City : The World Heritage.
Although the drafting of this Ministerial Declaration take a considerable period of time, it indicate a positive dimension on legal terms because of public involvement in consideration together with government sector in the locality.
Significant contents in this draft declaration emphasize on scale, density, and characteristics of buildings in the entire project area which is intended to bring about a more comprehensible order, harmony, continuity and identity of the ancient city. However, scientific criteria in this regulation is to be considered in detail upon completion.

A. Boundary : The City Island and surrounding areas

B. Regulations:
Area 1: The most important area general building height not exceeding 8.00 meters (floor to ceiling), governmental building not exceeding 12.00 meters (Floor to ceiling), water tank tower and public infrastructure not exceeding 15.00 meters (floor to ceiling)
Area 2: Building not exceeding 12.00 meters (floor to ceiling), water tank tower and public
infrastructure not exceeding 15.00 meters (floor to ceiling)
Area 3: Building not exceeding 15.00 meters (floor to ceiling), water tank tower and public infrastructure not exceeding 15.00 meters (floor to ceiling)
Area 4: Setback from important riverside 6.00 meters, height 15.00 meters and may be higher following setback line but not exceeding 30.00 meters
On Rojana Road height not exceeding 15.00 meters and may be higher following setback line but not exceeding 30.00 meters

C. Other regulations

- Architectural characteristics: gabled, hipped or traditional Thai style.
- Water tank tower: must be covered by roof.
- Antenna: to be installed in the most inconspicuous spot.

4. Act on Ancient Monuments, Antiques, Objects of .Art and National Museums B.E. 2504, revised (2nd Issue) B.E. 2535

This Act is the principal law for conservation and protection of monuments, antiques, and object of art. The Director-General of the Fine Arts Department is authorized, according to section 7, to specify and determine object and places to be protected ; section 7 (2) The Director-General is authorized to order termination and removal of any built object in case such object is done on the monument area without permission and the landowner has no fights to claim or sue the remover of such object.
Implementation under this act has great benefits on conservation because of the total authority of the Director General of the Fine Arts Department and the severe punishment. However, the result of this act has also brought about severe negative effects.
The Ayutthaya Historic City Project Office has, by this act, declared the entire area of the city Island approximately 8 sq. kms., as registered monument area on February 2540 BE in which any construction by either government or non- governmental body must be approved by the Fine Arts Department. Regulations on building and activity control, land-use, size, height and architectural characteristics are clearly specified as previously mentioned in the Ministerial Declaration to be enforced in B.E. 2540.