Davis had previously applied for patents for other inventions. Realising the potential value in his reinforced jeans concept, in 1872, he approached Levi Strauss, who was still his supplier of fabric, and asked for his financial backing in the filing of a patent application.
Strauss agreed, and on May 20. 1873, US Patent No. 139,121 for "Improvements in fastening pocket openings" was issued in the name of Jacob W. Davis and Levi Strauss and Company. That same year, Davis started sewing a double orange threaded stitched design onto the back pocket of the jeans to distinguish them from those made by his competitors. This trademark feature became Registered U.S. Trade Mark No.1,139,254.
According to wikipedia