Which preposition to use with sui

in Occurrences 7%

Consequentèr huic regno Turciæ ad Occidentem sui in ciuitate Cathasa

at Occurrences 1%

After the annihilation of the T'u--hun by the Sui at the very beginning of the seventh century, a new political unit had formed in northern Tibet, the T'u-fan, who also seem to have had an upper class of Turks and Mongols and a Tibetan lower class.

en Occurrences 1%

En lo sesoun qe l'erbe poynt E reverdist la matinée E sil oysel chauntent a poynt En temps d'avril en la ramée, Lores est ma dolur dublée Que jeo sui en si dure poynt Que jeo n'en ai de joie poynt, Tant me greve la destinée.

Which preposition to use with  sui