The term consumpta pecunia, money used, in D. 12,1 is interpreted differently in the legal tradition of East and West, when it came to explain why a condictio was granted to recover money, lent by an unauthorised person. In Byzantine law, the sixth-century antecessor Stephanus interprets this condictio as an enrichment action, namely . .p. .a... dapa..μ at.. ...d..t..... (condictio de bene depensis). For Stephanus money, once used, causes ownership to pass by commixture. He considers the condictio in the Digest as a unitary doctrine and views the titles D. 12,2 and D. 12,3, which deal with other matters, as a parenthesis. In the Glossa Ordinaria, this condictio has been interpreted as a contractual condictio, namely as a condictio ex numeratione or condictio ex consumptione. In the Glossa ordinaria consumpta pecunia causes ownership to pass by the validation of the contract. D. 12,1 is considered to be an independent title. The condictio in D. 12,1 is a contractual condictio; the condictiones discussed in the other titles are different, they arise ex bono et aequo. © 2013 Koninklijke Brill NV, Leiden.