The Brihadeeswara temple is dated to 1010 CE — the year of its formal dedication. The date is uncontested in the scholarly literature, supported by multiple converging sources, and crosschecked by twentieth-century survey methods. The temple is, in 2026, one thousand and sixteen years old.

How we know is more interesting than the answer. The dating evidence is, by the standards of medieval Indian buildings, unusually complete. The temple was built by a state that wrote things down, and what they wrote down is still on the building.

The short answer.

The temple itself names its date. A long dedication inscription on the south wall of the plinth, in Tamil, opens with the formula swasti shri… and records the consecration as performed in the twenty-fifth regnal year of Raja Raja Chola I. Raja Raja was crowned in 985 CE on the standard chronology. His twenty-fifth regnal year is accordingly 1010 CE.

The dedication inscription.

The inscription is several thousand characters long. It records the date, the patron, the principal donor, the deity (Shiva as Rajarajeswaram — “the lord of Rajaraja”), and a long list of endowments. The text was first read and translated in the 1880s by the Madras Epigraphical Department under the direction of Eugen Hultzsch; a definitive edition appears in the second volume of the South Indian Inscriptions series, published by the Government of Madras in 1895 and republished by the ASI.

The 1895 edition has been re-collated and re-photographed several times — most recently by the Tamil Nadu epigraphy department in 2010 as part of the millennium-anniversary re-documentation. No subsequent re-reading has substantively challenged the original date.

Regnal-year dating.

The Chola inscriptions do not use a fixed era (Saka, Vikrama, Kali). They use regnal years — “in the twenty-fifth year of the reign of His Majesty Raja Raja”. Converting a regnal year to a CE date therefore requires a fixed point for the accession.

The fixed point is well established. Raja Raja's accession is dated to 985 CE by cross-reference with the Sri Lankan Mahavamsa (which records his conquest of Anuradhapura), with Western Chalukyan inscriptions of his rival Satyasraya, and with independent regnal-year mentions in subordinate Chola inscriptions whose Saka-era dates can be independently fixed. The cross-checking is thorough; the date of 985 is held to within about a year by all serious scholars.

Pichard's 1995 survey.

Pierre Pichard, the French architectural historian, completed a comprehensive photogrammetric survey of the temple in the early 1990s, published in 1995 by the Archaeological Survey of India and the École française d'Extrême-Orient. The survey is the standard architectural reference for the building.

Pichard's work confirmed the dating in two ways. First, by stratigraphic analysis of the plinth — the inscriptions are integral to the original construction, not later additions. Second, by stylistic comparison with other dated Chola monuments of the period — the temple is consistent with the early imperial Chola style of c. 1000 to 1020.

ASI millennium re-survey.

The Archaeological Survey of India conducted a millennium re-survey of the temple between 2007 and 2010, in preparation for the thousandth-anniversary celebrations. The survey included structural monitoring of the vimana settlement, re-collation of the inscriptions, dendrochronological dating of surviving timber in the inner sanctum, and comparative analysis of the organic adhesives used in the upper storeys.

None of the survey's findings challenged the 1010 CE date. The dendrochronological sample from the timber of the inner sanctum's ceiling supported a tree-felling date within the first decade of the eleventh century. The adhesives matched the dated materials of contemporary Chola temples whose dates are independently fixed.

Other dating methods.

Radiocarbon dating cannot be applied to granite. It can be applied — and has been — to organic materials in the temple: the timber elements, the lime-and-palm-jaggery adhesives in the upper storeys, and a sample of bone in the consecration deposit recovered during the 1980s ASI repairs. All three samples produced dates consistent with the early eleventh century within the precision available to the technique.

The thousandth anniversary.

The temple celebrated its thousandth anniversary in 2010, on the calendrical date corresponding to the medieval dedication day. The celebrations were organised by the Tamil Nadu state government in concert with the HR&CE department and the ASI. The Reserve Bank of India issued a ₹1,000 silver commemorative coin — the highest denomination commemorative coin in independent Indian history. Postal stamps, scholarly conferences, and a six-month public exhibition at the Tamil Nadu state museum all marked the year.

The simplest answer

The temple is a thousand years old because it says so on its own south wall, in a language we can read, in a regnal-year dating system whose conversion to CE is well established, confirmed by stratigraphic, stylistic, dendrochronological and radiocarbon analysis. Of all the dates we hold for medieval South Indian monuments, this is the most thoroughly evidenced.