The Polish-Lithuanian armorial clan Kotwicz, bearing a coat of arms blasoned Argent, a fess Gules, produced several secondary offshoots, presumably as the result of heraldic augmentations: Kotwicz II (Argent, a pale Gules), and from the latter, Strzal/a (Gules, an arrow, barbed and flighted, point upward Argent), Siestrzeniec, and Siekierz (Gules, per fess embattled in three parts, the center conjoined in chief with a chevronel couped and debruissed of a barrulet Or, Argent).

Altogether more than eighty different surnamed families are theoretically related in these clans by blood or sometimes by adoption. The Kotwicz clan is said to descent from several brothers of a family called Buchheim, Puchheim, and Pöchner from Vörklabruck in Upper Austria, who moved first to Lusatia, and subsequently to Silesia, Poland, and Lithuania. The name Kotwicz is said to derive from a location in Lusatia where they constructed a castle, later known as Cottbus.

Siebmacher mentions a theory found in some early sources stating that Buchheim derives from the Scottish Buchan, as the family originated from members of the family of the Comyn Earls of Buchan who emigrated from Scotland to Austria early in the Middle Ages.

The Kotwicz, Kotwicz II, and Siekierz arms may be seen illustrated at: http://akromer.republika.pl/armorial_pocz.html