Thatbyinnyu, the climax of the Middle Period (1120-1170) of Pagan temple-building, was built by Sithu I (1113-1170) towards the end of his reign. The temple's monumental height is achieved by piling one great cube on top of another, even larger, cube to form the two storeys of the building. The smaller structure at the northeast corner is a so-called "tally zedi," which was built using one brick for every 1,000 bricks of the larger temple, according to the Lonely Planet Guide (p. 295).