In early 2003, Turbine released a timeline called The History of Auberean. We are presented with several events, and the year the occurred on both the Portal Year and Roulean calendars:
| Portal Year | Roulean Year | Event |
| -1441 PY | 324 RC | Jojiism founded.[1] |
| -869 PY | 704 RC | Viamont invades Aluvia. The reign of Pwyll II ends and the reign of Alfric begins.[2] |
| -779 PY | 765 RC | Reign of Alfrega begins. Harlune stays behind on Ispar during an expedition.[2] |
| -758 PY | 779 RC | Reign of Osric begins.[2] |
| -540 PY | 924 RC | Gharu'n armies seige the Roulean capital of Tirethas.[3] |
| -358 PY | 1046 RC | Emperor Kou unites the Sho under his rule.[3] |
With multiple matching pairs of dates, we can determine the equation to convert between calendars. All we have to do is treat the pairs of dates as coordinates of points, and find the equation for the line that intersects those points. We will determine the equation for each set of points:
| Point A | Point B | Equation |
| (-1441, 324) | (-869, 704) | |
| (-1441, 324) | (779, 765) | |
| (-1441, 324) | (-758, 779) | |
| (-1441, 324) | (-540, 924) | |
| (-1441, 324) | (-358, 1046) | |
| (-869, 704) | (779, 765) | |
| (-869, 704) | (-758, 779) | |
| (-869, 704) | (-540, 924) | |
| (-869, 704) | (-358, 1046) | |
| (-779, 765) | (-758, 779) | |
| (-779, 765) | (-540, 924) | |
| (-779, 765) | (-358, 1046) | |
| (-758, 779) | (-540, 924) | |
| (-758, 779) | (-358, 1046) | |
| (-540, 924) | (-358, 1046) |